I just got my 55ST60 last night. I got one of the first ones in Canada because it was a replacement for my 50ST50 that I bought on boxing day a few weeks ago. The ST50 failed after 4 weeks and Panasonic refused to replace at first making me go through two failed repair attempts that took over 4 weeks to implement due to waiting for parts.
I love the picture on the new set. I think it is if anything slightly better than the ST50 but it has been so long since I was able to watch the ST50 that it is hard to compare. It seems to me that it has more picture adjustment options and includes pro settings adjustments which I do not remember being on the ST50. I think it does a better job with my 1080i cable box signal than my other set. It also has a much enhanced set of apps that make it quite useful as a media player and DLNA network player. I was able in a few minutes to hook up to my LAN and access media of all types in a wide variety of formats on my network hard drive. As long as your network hard drive has some kind of DLNA server program built in you will not need to have any computer running to set up the TV for this type of access to a movie library. I do not think the ST50 had that capability, but I only looked for it briefly on that tv before it failed.
The other thing I noticed was that the default settings for the various picture modes (standard, vivid, home theatre, cinema, and custom etc.) seemed to be quite watchable without much adjustment. I am used to most tv's I have purchased including Sony, Samsung and prior Panasonic models, to take a lot of adjustment to get to something that approaches natural color, brightness and contrast. And the blacks are outstanding even in the "light" setting, just as they were on the ST50.
All in all I think they have another winner here, but of course that is based on only a few hours of viewing. I certainly hope this model lasts longer than my ST50.
I do have a couple of knocks though for the product and Panasonic. First, it appears that they have changed the 3D eye wear technology again for this model year, rendering the four pairs of glasses I purchased for the ST50 totally useless. They have added two pairs of new 3D glasses to the box, but this is still a disappointment, especially because the new glasses have no charging mechanism and it appears you have to replace batteries regularly, although there are no instructions included on that either in the eyeglasses wrapping or in the manual or quick start guide. I have looked on line for a time this morning but can find no user guide or instructions for these new glasses, and they are not even mentioned on the Panasonic sites in the US or Canada at this point.
Finally, Panasonic and its Concierge service has let me down big time. Because they sold me defective TV and refused to replace it when it broke down, I had to wait around for over 5 weeks with an unwatchable TV, have someone at my home on 3 occasions for the authorized repair person to come in to attempt repairs, then I had to drive my broken tv over 300 kilometres to the store where I originally purchased it. Even worse, Panasonic refused to pay the full cost for an acceptable replacement. Of course there were no 50ST50's available anywhere after New Year's day. The retail dealer had no new 50ST60's yet and was told they would not arrive until mid April. My only option then was to take a new 55ST60 that had just arrived, but to pay an additional $300 plus tax for the exchange. In addition I was stuck with 4 pairs of Panasonic 3D glasses for which I paid over $200 dollars. In short, because of Panasonic's failure to stand behind its products, their defective TV ended up costing me an additional $550 dollars.
I contrast this to a few years ago when I bought a new 46 inch Sony XBR9 LCD from Future Shop on boxing day. After about 4 weeks I noticed a dead pixel in the middle of the screen. I had a new replacement model in my home in less than 48 hours. Unfortunately the lesson here seems to be, don't buy Panasonic and buy from large box stores rather than smaller retail outlets like Powerline Electronics in Guelph Ontario. Too bad because the quality f the picture on their plasmas is unbeatable.