I have been using the BDT500 for a few days now.
Compared to my BD55 both the picture and sound are a huge improvement. When Bit-streaming music Cds and MP3s to my Denon 2809CI via HDMI the lows and highs are clearer and more detailed - very easy to notice the improvements. I know people say when Bit-streaming digital is 0/1s and wouldn't change, but believe me I notice a big improvement and so does my neighbors. I am using the "
High Clarity" sound reproduction setting in the BDT500.
As far as Blu-ray - the picture is smoother and more detailed with improved clarity that is very noticeable due to better edge definition and improved richer/cleaner color reproduction. The motion smoothness is also improved. High definition sound is also improved - very crisp and clear sounding. Compared to the BD55 it loads and starts Blu-ray and DVD disks blazingly fast.
The remote sucks. I am slowly getting used to it but I am now using the remote from my BD55. It is sooo much easier to use, and ALL functions of the BDT500 work just fine with the BD55 remote

. The BDT500s responsiveness is very quick when using either remote - much faster than the BD55. The biggest aggravation and disappointment of the new remote is that you can't program the volume to adjust anything except a Panasonic television - really stupid!
Addendum: Be sure and go to Panasonic's website to download firmware version 1.31 update (released May 21, 2012). It doesn't improve/fix any sound or image issues, but it does improve "
VIERA Connect" and "
Wireless LAN Connectivity". My BDT500 had version 1.21 installed.