The really impressive thing about the ST is that with proper calibration it can indeed reproduce cinema quality. A reference picture is attainable. You also get a real sense of depth to the 2D picture. Both the 2D and 3D out of the box performance was still impressive to me. I used a copy of Disney's WOW calibration disc for basic and a quick set-up whilst I waited for my friend to fit me in for a proper calibration. For anybody that can't afford or get somebody to do a proper calibration I highly recommend the Disney disc. It's quick and easy and improves the picture substantially enough to be worth the time (1hr) effort and minimal cost. (it's probably worth buying just for the pixel flipper it comes with tbh)
It's because of the PQ when calibrated I decided to get the ST over paying more for the GT or VT. It really wasn't worth the extra and i also wasn't keen on the darker picture the GT and VT seemed to give off and was blamed on the thicker light filter on those panels. Being a Panasonic plasma as the panel ages the black levels should do nothing but improve either as all their previous models have. Like a good wine improving with age

This is also backed up by a few comments made here by people with older Panasonic models getting a great picture it seems.
The ST is not perfect however. Much has been made of the vertical banding on the 2012 models and yes it is an issue worth mentioning. It's an inherent flaw in the 2012 panels. Every TV being a bit different it seems as to how much it's exhibited.
I can only talk for my own TV. I have not had to return mine. That's not to say i have no banding, I do. I have 1 band that is about 1 inch wide near the left side. Some people have a lot more bands on their ST50's and return them for a replacement. So you might need to replace before you get a good one.
There is no panic though as the vertical band I refer to is very, very hard to see and i only ever see it if I look for it on a grey screen. The only time iv'e seen it in real world use is once when I was watching football and I had forgot to switch my pre configured settings over to my Sport setting.
I can try to take a photo of this on my TV if it bothers anybody considering buying one and needs to see but to me this is a non issue and I think is even lesser of an issue on the smaller 42" but something I should mention and will add this in no way should put you off considering this TV as the pros way outweigh the one con in my case.
A reference PQ (or as damn as close to) at the ST's price is quite something and not to be ignored.
I know of 2 well respected TV reviewers who went out and bought themselves ST50s after reviewing them. That alone should give you some idea how good they must be.
I watched The outlaw Josey Wales last night on BR. I sat open jawed the whole movie I think. That is one stunning BR disc guys. 1976? It looked like it was made yesterday!
I have 2 issues with my ST...
1: It has rendered my DVD collection useless as anything other than 1080p on this TV is a crime.
2: I wish I had got the 55" now.