The FiOS connection offered a bit sharper image without any hitches, but the DSL connection worked smoothly enough (I streamed a World Cup match). Sling engineers have done some impressive work with video compression schemes and buffering to achieve decent results from even slower connections.
If you're dealing with relatively poor bandwidth, the video does get downgraded to standard definition or worse (yes, the picture can get a little fuzzy at times but the sound always seems to come through).
I also used the iOS and Android apps and you receive a generally crisp picture on your phone or tablet, particularly if you're on a Wi-Fi network with a good Internet connection (streaming video using a 4G connection usually works quite well, but you will eat up a lot of data very quickly).
At home, where I have a speedy Internet connection, the image on all my mobile devices and computers is rock-solid; it's as if I'm watching regular TV.
I have a TV in the kitchen that has a Roku box attached to it but no cable box (it has a QAM tuner that allows me to get basic channels). Using the Roku and Sling app on the iPhone I can "sling" my full selection of FiOS cable programming to the TV. It's not a totally intuitive set-up, but using your iPhone as a remote works well enough. (You can also do the same thing on an Apple TV box using AirPlay from an iPhone or iPad app.)
If you're looking for differences between the M1 and SlingTV, the SlingTV has an HDMI pass-through port that allows you to navigate your home TV's programming via Sling's well-designed electronic programming guide and a few other extra features. Sling's EPG (electronic program guide) uses a tile-based interface similar to the one found in the SlingPlayer for iPad's Media Gallery. However, from the standpoint of remotely accessing your home TV's programming, you really don't lose anything by going with this more affordable model. It offers the same remote streaming features and uses the same mobile apps.
Several years ago, when it was first released, the Slingbox was a truly groundbreaking device. It was a great way to watch your home TV from wherever you were, even overseas, and came in especially handy if you wanted to watch your local sports teams while you were on the road.
Today, it faces increased competition from "TV Anywhere" apps from cable and satellite providers, but a lot of those apps still offer limited channel selection -- or they don't work outside of your home network. Until those apps truly open up, the Slingbox remains the best way to remotely access all your home's video content, and the M1, with its built-in Wi-Fi, is an attractive place-shifting solution at its more affordable $150 price point. It's an easy recommendation for sports fans or anyone else who really values the ability to access live TV anywhere.