I just got my 6500.
On the 4100, trick play with MPEG2 1080i/60 and 720p/60 TS files is borderline.
It approximatively works with high bitrate TS files (like CBS files), and not at all with low bitrate ones (like Fox files).
I was hoping that the faster processor would fix that on the 6500, but even with the last firmware, it's a total failure.
Going back 15 seconds actually goes forward several minutes, and the direct GOTO function scans to anywhere but the indicated time-stamp.
If you want to watch US TS files, the 6500 in its actual state is totally un-usable. There is just no way to reliably seek into a file, you have to watch it from the beginning and let it run.