If you're shopping for a 2012 TV and picture quality is your highest priority, you should, in ascending order of financial recklessness, get a plasma, splurge for an Elite or wait and buy an OLED. If getting the best picture for your money is your highest priority, you should get the Panasonic TC-PST50 plasma -- although the Samsung PNE6500 is a very close second-place. At press time both cost hundreds less than the Panasonic TC-PGT50 reviewed here, and offer picture quality that's just as good.
That's not to say the GT50 isn't worth recommending; it's just a tweener whose reputation suffers the tarnish of comparison--both at the hands of better values like those two, and better performers like its bully of a big brother, the VT50. I love baby G's styling; its feature set is all I could ask for, and its picture quality is among the best of any TV I've tested. Its one seeming advantage over the ST50, a THX mode that promises picture quality similar to a professional calibration, just isn't good enough to be worth the extra money. If you have other priorities, however, such as premium design in screen sizes beyond those of the VT50 series, the GT50 still has plenty of appeal.
I called the VT50 the best-looking Panasonic plasma TV yet, but the GT50 isn't far behind. It eschews the comparatively chintzy transparent edging of the ST50 for metallic, sharp-edged silver that makes a beautiful accent around the thin black bezel.
Last year I ranked Panasonic's Smart TV interface, called VieraCast, highest for its simple layout and ease of use. The company didn't change much beyond the name -- it's now VieraConnect -- for 2012. Navigation and app launching was a bit faster than on the ST50, likely thanks to the dual-core processor, but once I was within an app I didn't notice any differences in reaction time.
Panasonic's content selection is top-notch since it added Vudu, although I'd like to see a dedicated 3D app like LG and Samsung offer.
Viera Connect has more advertising than other TV makers' Smart TV systems. The TV actually shows you a banner ad when you first power up. It popped up and lasted only about three seconds, but it was till annoying. Here's how to disable it. Like many TV makers Panasonic also reserves a spot on the Smart TV home page for an ad, and there's no way to remove it.
The GT50's THX modes are quite good by default, and unlike on the 65-inch VT50 I reviewed, their light output is not limited overmuch. That's more a function of screen size than any difference between the two series, I'm guessing. Either was I really appreciated that both THX Cinema and THX Bright Room offer basic adjustments--an improvement over LG's non-adjustable THX.
The only mode to offer advanced controls is Custom, which unlike the others also allows different settings for each input. Its Pro section gets a two-point grayscale control and a few gamma presets, along with a bunch of less-useful stuff like Black Extension and AGC, both of which sound be set to zero. Along with the VT50 from Panasonic's own line, LG and Samsung both offer 10-point (or higher) grayscale settings, along with full color management, in their plasmas--making the GT50 the least calibration-friendly plasma at its price point.
There's no meaningful difference between the GT50 and the ST50's picture after both are properly calibrated. Both are outstanding performers, among the best plasma TVs I've ever tested, and just shy of the picture afforded by the much-less affordable TC-PVT50 series. Samsung's PNE6500 and PNE8000 scored the same as ST50 and the GT50 in this category, but I'd pick the Panasonics because of their slightly better light output (at least compared to the 60-inch Samsungs).
I mentioned calibration because that's how I compare all TVs--only after adjusting their picture settings to the best of my ability (and since I publish my settings, readers can get their own TVs very close to what I see and compare in the review). But you might be wondering whether the GT50 can beat the ST50 before both are properly calibrated, since the GT50 has the THX modes and the ST50 does not. Comparing the GT50's best THX mode to the ST50's best mode, Cinema, I found that THX Cinema was slightly superior in grayscale and gamma, but dimmer and thus less punchy overall. Of course you can increase the liht output of THX Cinema on the 55-inch GT50, eliminating that difference, but even after that THX on the GT50 isn't that much better than Cinema on the ST50--certainly not worth the price difference alone.