"Good TV except for THX mode"2.0 starson by KidHorn
Pros: Good picture in custom mode.
Cons: THX mode issues on older TVs.
Summary: THX mode has a known defect for older TVs. If you buy a TV that is manufactured prior to a certain date, the THX mode will look overly green and yellow. I don't know the exact date, but it seems like it's likely in September or October 2009. Panasonic is aware of the issue and has not been able to fix it in older TVs, so if you buy one that was made several months ago, you may not want to use the THX mode. The problem can't be calibrated away. It also doesn't seem to effect the 65 inch TVs.
This is a bummer to me since I got one of the bad TVs and I wanted to use the THX mode. I calibrated the custom mode to produce a good picture, but it doesn't look as good as THX mode on a properly working TV.
Otherwise the TV has been perfect. It's a shame my TV can't be fixed and I doubt Panasonic would replace it.
There's also an issue of HDMI handshaking with certain Onkyo receivers. I think Panasonic can fix this if you specifically request a certain firmware version and know how to install it. The fix isn't part of the normal firmware update cycle.