We also have a new[er] Sony LED set, its a mid-upper model, good, but still prefer the plasma downstairs.
That's the thing - a plasma tv needs a dark room, in a bright room during the day you might as well give up and turn the tv off.
I bought a top-of-the-range Panasonic plasma from the GT range and it has to go down as the worst purchase I have ever made. I have never been so very disappointed in a tv set. ..
I'll take a higher range LED tv be it the upper tier Samsung (8000 series) or some of the other great sets out there any day. Panasonic is good too if you want to stay on a budget yet still get good angles, passive 3D (much better imo than active 3D), and a fantastic menu-system which gives you more control over the picture than I've ever seen.
To get a truly great tv you might even have to dig deeper for some of those (slightly) older models which aren't edge-lit but have a full-LED array behing the screen, which means they are not ultra-slim but a little bit thicker since the lights are all behind the panel. Those - coupled with local dimming - are truly superb.
But people want slim tvs, even when they're not mounting them on a wall, so companies have shifted away from this just to shave off a bit of the thickness.
Overall my advice for today would be to get the best value for money and buy something at a low price instead of investing into something fancy and expensive. Things are currently changing with 4K, OLED, etc., so now is not the time to buy something that is meant to last a long time. Best to get something that gives you great value for the buck (which is incredibly easy these days) for the next 2-3 years and then consider upgrading once the changes have been made and prices have settled.