I have the Hitachi 42HDS52 and I use a Sony DHG-HDD250, an HD DVR. I have intermittent lip sync problems with both my digital sources which are a Cambridge Audio DVD79 DVD player and the DVR. The weird thing is that the problem I have is the opposite of what most receivers and other components compensate for, which is the same mentioned here, that the audio is ahead of the video. Most components I've seen that provide a method to compensate for lip sync add a video delay because the sound comes before the video due to the delay involved with the video scaling/processing, and this includes my DVD player. Obviously this doesn't help so I'm in the same boat as others here...
All that aside, I am extremely pleased with the picture quality of the Hitachi plasma. I keep an eye out for models in the same price range and have yet to see one that looks as good for the price ($3k), the panasonic's being a close second. Hitachi's ALIS technology (closer pixels) creates a nice smooth-looking screen, with less of the "screen door" effect that is noticeable on most plasmas. If I could do it again, I'd buy the HDT series (same tv, more outputs) for a few hundred more to get the firewire output, but I'm not crying about it yet :).
All that aside, I am extremely pleased with the picture quality of the Hitachi plasma. I keep an eye out for models in the same price range and have yet to see one that looks as good for the price ($3k), the panasonic's being a close second. Hitachi's ALIS technology (closer pixels) creates a nice smooth-looking screen, with less of the "screen door" effect that is noticeable on most plasmas. If I could do it again, I'd buy the HDT series (same tv, more outputs) for a few hundred more to get the firewire output, but I'm not crying about it yet :).