I have the 46V5100. The only issue I ever really had with it was the red flashing (which drove me crazy). Ever since I installed the "unofficial" firmware that fixed the red flashing (a year or two back), it has been working great. My main uses are over-the-air HD, Blu-ray, and a media streamer box. I have intentionally not upgraded to newer "official" firmware versions out of fear that something would break.
Actually, my only complaint with the TV is that it will only output 2-channel PCM (via the optical output) and not the full 5.1 bitstream. Had I known that when I bought it, I probably would not have gotten it. Oh well.
Now, however, I fear the TV's days are numbered. It still works great, but lately I've been thinking it might be time to get something a little bigger (about the 55" size range) now that it is in a new location at home. Will my next one be Sony or not? Hummm, right now I'm kind of leaning to "not". We'll see.