Caveat: the new Philips 42PF7520D/10 is the only plasma TV I have owned, so some of these comments may be specific to this TV and others could apply to all plasma TV's.1) A friend's older plasma TV had loud fans that came on after a few minutes - the Philips has no discernable noise.
2) The visible banding on graduated dark shades is disturbing. I would suspect this is true of all plasma TV's, and that's why the demo videos in stores are always bright digital cartoons. I don't know why reviews don't emphasise this issue, as the resolution, brightness and contrast are fine but the posterizing/banding due to lack of colour depth is immediately obvious.
3) The TV takes quite a while to power on - manual says "less than 30 seconds should be considered normal". Longer than you would expect from a TV, that's for sure.
4) Backlight (or something like it) stays on for 5+ minutes after power off. Not good when with TV in our bedroom and lights up room after lights-out... Manual says "this is normal" with some nonsense about the TV searching for possible software updates. Probably not an issue in the living room.
5) Remote was designed by someone who has never met an average user. It's symmetrical top/bottom, so it is 50/50 whether you pick it up the right way round. Has classic design error of most buttons being the same small size (e.g. the "guide" button and the button that switches sound mono/stereo). I use the former every time I use the TV, and have never used the other button.
6) The program "guide" is an afterthought not designed into the TV/remote. The "guide" button is well placed, but the "info" button that tells you about each program is *really* hidden away. The first-generation interactive guide has a poor layout: you can't simply scroll a channel guide forward in time to see what's on in maybe an hour, and the guide uses the entire width of the TV to list one program at a time, instead of the grid view with programs by half-hour segment. What's wrong with a simple channel/time grid you can scroll through and click on???
