Thanks to this thread, I picked up a 50PK550 earlier this week. It's my first HDTV, coming from a 60" rear projection behemoth.
Maybe I'm just lucky, but in the few days I've had the TV, I can't say I've noticed any IR, although I am trying to be mindful about black bars, and have been keeping any 4:3 content on 'Zoom' mode.
PQ is fantastic to my eyes, my jaw dropped when I started up Avatar in 1080p. I hope that it will only get better as the set settles in.
The screen is pretty reflective, but unless I think about looking for reflections, I don't really notice. I have windows on either side of the set (but no direct sunlight), and while the picture is a little washed out, it's certainly not unwatchable. I don't actually use the set much during the day though anyway, so I'm not worried.
My only gripe is the lack of Stereo Audio output. My receiver is old, and even though it's on the list to be replaced, I'm still stuck with it for now. It doesn't even have a remote, so it simply acts as an amplifier. That means that volume control is by device, and always changes depending on what I'm watching.