http://allpointsnorth.co.uk/2008/08/05/i-interviewed-steve-wozniak-once-seriously-i-did/
Steve Woz considers the 8500 one of his favorite Apple products.
I met Woz some years ago and I asked him about his favorite Mac and he said exactly what he said in this interview. Actually at the time I thought he had said the 8600 which didn't honestly make much sense to me. I had an 8600 (Kansas) that had been upgraded with a G3 card but honestly there were so many random problems with the design it that I couldn't understand why it would be his favorite. I was always tinkering with that machine to get it working. I had a DOS card in it at the time and ironically the Windows and DOS environment was more stable than the Mac environment on that machine. Realizing that it was really the 8500 makes more sense to me.
Cool. I am just now getting my hands on a WGS 8515 and it will be my first 604e Mac. The 8600 (mentioned above) had been upgrade with a G3 card and the 604 CPU card was long gone. The 604 was the one class of PowerPC missing in my collection. I would like to keep it a 604e and it would even be awesome to find a 604-based upgrade card. (Or as Bunsen mentions maybe even a dual 604 upgrade card.) Everyone seems to run to the G3 but I have more than enough G3s around. Adding another one is pointless.
As for liking a processor, I have to say that I really like the PowerMac 6500 and the 603ev chip. When I bought my 6500 many years ago I had planned on using it as a server system. It performed that role dutifully for quite a while but even after I retired it as a server I used it for odds and ends and came to really like it as a really solid machine. The 603ev always impressed me because not only did it get to some nice clock-speeds but it was a tiny and power-efficient chip. I came to think of it as 'the little Mac that could.'