I got my PSR-500 from Scanners Unlimited today, a day earlier than promised. As usual, Glenn was a pleasure to deal with. Mine does not have the uneven window or loose antenna problems others have mentioned. Getting my local trunked system loaded was trivial, thanks to the V-scanner folders (and preloaded data courtesy of Radio Reference, which is prominently credited in the printed manual). Audio is very clear, and the help text is a huge improvement over other (mostly Uniden) scanners I have used. Ease of use is far, far better than with recent scanners I have used. That should make the PSR-500 a lot better suited for those who aren't eager to wade through complicated instructions.
In brief side-by-side comparison with a BC796D, the PSR-500 seems slightly slower in picking up the start of a transmission. That could be a problem for very short transmissions. I freely admit that I haven't read the real manual yet, so I may be missing some tweak that would help that.
It's obviously premature to make a lot of detailed comments/judgments, but so far it looks like GRE has done a very nice job with this model. Now it's time to walk over to Don's place and grovel for a copy of WIN500 light.