I can't help you really, except to say that I've bought a PCR2500 and while browsing the internet for info on it saw a post somewhere from a guy who said he'd sold his 8500 after buying a 2500, on the basis that he was content he wouldn't need it anymore.
Not much to go on really I know.. but it helped me decide to buy a PCR2500 as I'd originally wanted a 8500 but couldn't afford it!
If I can find a link to it I'll post it.