When you buy a new TV a crucial decision is how much you're willing to pay for improved image quality. Just about any cheap TV these days delivers a "good enough" picture but if you want to realize the benefits of the best-quality sources -- specifically 4K video with high dynamic range and gaming-friendly extras -- you'll need to spend more. The Vizio M-Series Quantum offers step-up features that let it outshine cheaper models, but it remains eminently affordable.In my side-by-side tests, the M7 couldn't match the picture quality of my favorite TV for the money, TCL's 6-Series, but it also costs a lot less. It's bright enough to bring out highlights in HDR and still put out relatively deep black levels, resulting in an image with plenty of punch and contrast for the price. And it's the cheapest TV on the market with Variable Refresh Rate, a gaming feature found on PlayStation 5 and Xbox Series X\/S (and some video cards) designed to reduce tearing and other artifacts. The M-Series also comes in a wallet-friendly 50-inch size, while most good-performing TVs start at 55 inches. Add it all up and you have an appealing package for anyone who doesn't want to spend up for the TCL.DesignExternally there's not much to differentiate the M-Series from other TVs on the market. Its color is all matte black, with a slim plastic border on the top and a thicker, metallic bottom edge above spindly stand legs. The look is decidedly middlebrow.Vizio's basic remote got a facelift this year, with more rounded keys and a prominent "WatchFree" button to join more recognizable streaming service shortcuts such as Netflix, Hulu and, uh, Redbox at the top. Otherwise it's pedestrian-looking with too many buttons, and I prefer the simpler, more focused clickers of Roku or Samsung. The company has made more changes to its SmartCast system but again it falls short of Roku or Android TV, or even LG or Samsung's proprietary systems. The main home page is packed with TV show, movie and channel suggestions you probably don't care about, and the stuff you'll probably use most -- the streaming apps themselves -- are denigrated to a single row.Although the platform now has 64 apps, including most major names, it's still missing heavy hitters like HBO and HBO Max, Sling TV and ESPN. And finding new apps is a pain: Instead of a simple channel or app store that lets you search for, add and delete apps, you have to scroll the row through to find what you want. You can arrange app tiles to taste but I was also annoyed that none of them can be deleted. The search function in the upper left of the home page only finds TV shows, movies and videos, not apps themselves -- I searched "HBO," for example, and the most relevant results were YouTube videos. In its favor, search results do span different apps including Apple TV, Disney Plus and Amazon Prime, but they don't include Netflix. Roku's search is much better in general.To watch any of the hundreds of apps that aren't part of Vizio's on-screen system you can use the cast function on your phone to connect to the TV. The TV supports both Google's Chromecast function and Apple's AirPlay. The M-Series doesn't have any voice capability built into its remote but the TV will work with Amazon Alexa and Google Home speakers.The M-Series Quantum is one of the cheapest TVs with full-array local dimming -- my favorite addition for LCD picture quality because it improves all-important contrast and black levels -- but different models in the M-Series have different specs. In short, the M7 I reviewed is less impressive on paper than the M8.The number of dimmable zones is an important specification because it controls how precise the dimming can be. More zones doesn't necessarily mean better picture quality, but it usually helps. The M8 is also brighter than the M7, at 800 and 600 nits respectively. I didn't review the M8 but based on these specs I'm guessing it performs a bit better than the M7, but not as good as something like the TCL 6-Series.The rest of the M-Series specifications are the same on all models. Quantum dots allow the TV to achieve better HDR color, which was borne out in my measurements. The M-Series has a 60Hz refresh rate panel -- Vizio's "120 Dynamic Motion Rate" is bunk. It lacks a setting to engage motion estimation and motion compensation (also known as MEMC or the Soap Opera Effect) as found on the more expensive Vizio P- and PX-Series, as well as TCL's 6 series. Vizio supports both major types of HDR, HDR10 and Dolby Vision, in the M-Series. So does every other major TV maker except Samsung, which lacks Dolby Vision support.Here are the M-Series' other specs:4 HDMI inputs1 analog composite video input1 USB portRF antenna tuner inputEthernet portOptical digital audio outputStereo analog audio outputNew for 2020, the M-Series supports eARC (on HDMI 3) as well as new gaming-centric features, namely Auto Game Mode\/ALLM and Variable Refresh Rate. This is one the least expensive TVs we know about that can handle VRR, a graphics feature found on the PlayStation 5 and Xbox Series X\/S (and some video cards) and designed to reduce tearing and other artifacts. It won't be as effective as TVs with true 120Hz input capability like Vizio's P series (the M-Series maxes out at 60Hz input), but it might be better than not having VRR. We'll know more when we have the chance to test this TV with the new consoles.Picture quality comparisonsWhile certainly not at the same level as the TCL 6-Series or Sony X900H, both of which scored an 8 in my tests, the Vizio M-Series' image quality earned a solid 7. That's the same score I gave the Hisense R8 Roku TV, which is in the same price ballpark as the M7, but if I had to choose I'd take the Vizio's superior contrast, processing and black levels over the R8's brighter picture.I spent most of my side-by-side time comparing it to the TCL and the Hisense H9G, both of which are more expensive. The Vizio fell short of the contrast and brightness of those two sets but in its favor showed an even-keeled, balanced image with good shadow detail and color accuracy. Click the image at the right to see the picture settings used in the review and to read more about how this TV's picture controls worked during calibration.Dim lighting: In late October The Invisible Man seems like an appropriate comparison movie, so I fired up the Blu-ray in my dark basement and tried to be brave. In dark scenes the Vizio was good but it couldn't match the inky blackness, or overall contrast, of the more-expensive Hisense and TCL. Throughout Chapter 1, as Cecilia Kass (played by Elizabeth Moss) pads around and ultimately flees her darkened house, the shadows, letterbox bars and night sky appeared markedly lighter on the Vizio than the other two, leading to a less realistic picture. Details in shadows were very good on the Vizio, however, matching the TCL -- I could make out more of the art and furniture in her bedroom (4:35) on both sets than on the Hisense. Blooming and stray illumination, for example in the pause icon and progress bar from my Blu-ray player, as well as the white-on-black "Two Weeks Later" lettering at the end of the chapter, was also minimal. Bright lighting: The M-Series was a decent if not spectacular performer in a bright room. With LCD TVs light output is one of the major things you pay extra for, so it's not surprising that the affordable M-Series is dimmer than many of the more-expensive TVs I've tested. It's still brighter than budget models like Vizio's V-Series, but at least one like-priced TV I reviewed, the Hisense R8, is brighter than the M-Series.Vizio's Calibrated picture mode delivered the most-accurate bright-room picture, which is well worth the loss of nits compared to Vivid in my opinion. The M's semi-matte screen finish reduced reflections better than the TCL albeit not as well as the Hisense, and was worse than either one at preserving black-level fidelity. Color accuracy: In its best picture modes, namely Calibrated and Calibrated Dark, the Vizio was exceedingly accurate according to my measurements even before calibration. In the The Invisible Man its image did appear just a bit duller and less saturated than the TCL, however, an issue that could be due more to a black level disparity than anything. As Cecelia sits at the dinner table for example (16:55), her skin tone looked a bit paler than the TCL, and the wood and plants of the kitchen looked less rich. Again the Hisense trailed a bit in color accuracy. In the end all three were quite accurate with SDR and it would be tough to point out differences outside a side-by-side comparison.Video processing: The Vizio M-Series behaved like I'd expect from a 60Hz TV in my motion tests, meaning it didn't reduce blur as well as higher-end sets with a 120Hz refresh rate. I'm not particularly sensitive to motion blur, but if you are, a true 120Hz TV like the TCL 6-Series or Vizio's P-Series might be worth a look.The M registered proper 1080p\/24 cadence but exhibited motion resolution of just 300 lines. Vizio does offer a Clear Action control that improves that number to a respectable 900, but as usual it introduced flicker and dimmed the image, so most viewers will want to avoid it (note that if you have VRR turned on, Clear Action can't be activated). Unlike some 60Hz TVs there's no option to turn on smoothing, aka the Soap Opera Effect.Input lag for gaming was good in both 1080p and 4K HDR, with a result of about 27ms in the Game picture mode -- that's a bit worse than the TCL 6-Series at 19ms but still perfectly acceptable. As usual with Vizio I appreciated being able to reduce lag in other picture modes too, such as Calibrated Dark, by turning on the separate Gaming Low Latency toggle. That yielded the same 27ms result, a big improvement over the 52ms (in 1080p) and 68ms (in 4K HDR) of lag I measured without GLL engaged. Uniformity: The M-Series had no major issues in this category, with a nicely uniform image across the screen and little or no variation at different light levels with full-field test patterns. In mid-bright full-field test patterns it showed a bit more variation than the other two, but in program material differences were tough to discern. From off-angle -- seats to either side of the sweet spot in front of the screen -- the Vizio didn't maintain black level fidelity quite as well as the other two, although it was roughly good at maintaining color.HDR and 4K video: As usual the biggest differences between displays emerged when I fed them the highest-quality HDR video, first from the Spears and Munsil HDR Benchmark Blu-ray. The Vizio looked very good with the montage of footage but the TCL and Hisense performed better. Both displays beat the Vizio for contrast -- with deeper, truer black areas and brighter whites. In the snowclad mountains, for example, the fields of white and cloudy skies were brighter on both, leading to better impact and pop, while in the night cityscapes and amusement park the TCL and Hisense delivered blacker shadows compared to the grayer Vizio.In its favor the M-Series kept blooming in check, with minimal stray illumination in dark areas around the honey dripper for example (2:48). Color was also good, with saturation and vividness a tick higher than then TCL especially in reds like the flower (3:30) and significantly more accurate overall than the Hisense, which appeared too garish and unrealistic in comparison.Turning back to The Invisible Man, this time on 4K Blu-ray, the Vizio again lagged the other two although as usual the differences weren't as drastic with a standard movie as they were with test material. Dark areas in Chapter 1, for example the depths of the walk-in closet and the go-bag cozy, were again inkier on the TCL and Hisense, leading to better realism. The Vizio did preserve shadow details best but the others were still solid and more impressive overall. The biggest difference, however, was in the brilliance of highlights, for example the strip lighting and fluorescents in the tech lab (5:37) -- compared to the other two, the Vizio looked much duller, without that characteristic HDR pop. In more balanced scenes, like the kitchen in Chapter 7 (25:38), the Vizio again seemed slightly duller than the others, with more muted highlights and washed-out dark areas like the cabinetry and shelving.