I just bought the UE46B8000. Its wafer thin and is stunning. Its upscaler is much better than anything I've ever seen and the picture is breathtaking (and I haven't even tried blu-ray yet.) The SD picture is like my old upscaled DVDs and at first glance looks HD. I've got a Sony 52 inch Bravia 2 upstairs and this new TV blows holes in it. There is some new guff on it (little stories for kids, cookery tips etc...fluff!
Strange stuff: The 200 mhz (240 in US I believe) makes upscaled DVDs a bit weird, you know when you are watching a behind the scenes shoot of a movie and all the colours are much more realistic and harsh before they do the post processing gloss over it. Well just watched Twilight and it looked like it was shot with my camcorder, all too real! I kinda like it but it does take getting used to as it takes away some of the immersive magic of the movie while making it seem so much more in your face. I'm describing this badly - just think difference between real News Reports and Hollywood depictions of news reports.
Imperfections, the backlight isn't perfect and on black screens there is bleeding and smearing (patches of not totally black on the screen). They have a weird circular button in the remote which surrounds the middle button, you select something with the middle enter button and then you can rotate the outside button to select sub menus. Nice idea but sucky since its so sensitive I find it hard to select and maintain the selection (I have to arch my thumb to stop catching it when I press enter. They also add a small pebble like remote that that just does power off, volume and channel up and down. Both remotes are ugly bugly imo. To make it internet capable you need an extra £50 dongle - tightwads. It's LED edge lit (think Christmas tree lights inside along the edges) but not true LED.
Improvements: My Sony does this nasty dimming thing where to keep blacks black it dims the backlight on scenes that are dark but it does it suddenly so you get all the light parts of the screen suddenly dim and look washed out and then the backlight fires up in the next scene and everything gets bright. This TV doesn't seem to have the same problem at all. Also the remote lights up when it gets dark so you can see all the buttons.
All in all - stunning, I totally recommend getting one since they are a major step up in quality for no great step up in price - and being edge lit they are super lightweight and about 5 times shallower than my Sony. I still get goosebumps watching it.