Sorry to hear rikky. It is a bit of a panel lottery. I got lucky. Did the one bad panel put you off enough to get a refund or did you get a replacement?
It is a hassle having to get a replacement and it certainly helps depending on where you buy from. Richer Sounds (for example) might be a little cheaper than John Lewis say but John Lewis will pick up and replace where as RS you will have to transport yourself. Worth considering.
Mine wasn't bad enough to warrant me seeking a replacement and the chances are any replacement I would have got would have been worse.
Although to say this years models have "massive problems" is a bit sensationalist. If there were any real serious issues or "massive problems" the product would have been recalled by now and it hasn't been and it won't be. Most people who buy this TV are happy with it. As is always the case people use the internet to complain. So all those that got a bad one complain whilst the silent majority are happy and enjoying their new TVs. Are there a lot of complaints? Yes. Why? Because they [Panasonic] have sold so many of these things
It's worth remembering that ALL modern TV's have some kind of drawback to them. The ST50 is no exception but if you get a good one then you will be happy. (I know somebody that had several replaced before he got one he was happy with)
Because of the chances of needing to replace or seek a refund it is most definitely worth considering who and where you are buying from.
These are not high-end plasmas but they do have a high-end picture so something has to give. We are talking about budget plasmas here after all and is something easily forgotten.
At least it isn't an issue that develops over time. It's something that is or isn't there from the start so you can make your own minds up right off the bat.
If you do buy from someone like Richer Sounds you do have the benefit that you can actually view the actual TV you intend to buy there. If anybody is doing this I recommend doing the following...
Ask to see your TV working. Once the salesman has your TV up and running ask him to navigate to the "software update" screen for you to view. (in network settings) This brings up a solid grey screen. This screen is the shade of grey that shows off those nasty vertical bands the worst (best?) If it looks good there you are onto a winner. On the other hand if there is any banding it will be all there for you to see instantly and you can ask for another.
As long as you buy wisely you should be in no way out of pocket should you get a TV you are not happy with so it's not like it's a risk.
and as always... view before you buy.