Well, I began to use GRE exclusively when they were the first to offer the RadioID feature. When I filled up my PSR-500 with RIDs to the point it ran out of memory, I bought the PSR-800 and couldn't be happier. I do have to admit, I liked the number pad on my 500 alot better than the 800 for mobile scanning, but the SD card with virtually unlimited systems, RIDs, alpha tagging and even the software puts GRE above Uniden IMHO and I'll be adding a 900 to my list. As far as simulcast systems go, the ROAM feature rocks.
Like I said, I just with they had an easier way to select scangroups like a number pad used with the function key like the 500 on the 900....and take that squelch knob and make it a volume control knob! Stick the cable in the rear for the remote vs the side and I'd say it's better than anything else out there. As far as a speaker in the head, buy a remote speaker or hook the jack into your vehicle's line in...scanning in stereo !