From Experience...
When I came by my 6320 my only other experience of PowerMacs had been the less than mindblowing Performa 6200. Why did I buy another then? Well, as the old expression goes, a fool and his money...
Despite the technical facts that the 6320 and the 6200 are just about the same machine, in practice...they're just about the same machine. The 6320 is just as dull, boring and uninspiring as the 6200 and from a usability point of view they both offered the same features: both had CD drives, both could be upgraded with 72 pin SIMMs, and both would run some apps that 68K Macs wouldn't. Even popping the hood (when you eventually figure out how to)(Tip: Take off the front, push the top forward and off, and then slide the side panels off) reveals nothing very interesting. I suppose the only item of any interest is the heat sink on the processor - hardly rivetting.
The 6320 was the first machine that threw OS 8 at me and first impressions of this were good. Ok so I was more concerned with the aesthetics rather than functionality but it's a decent little OS and has some nice features that mark it out from OS 7 (again, mostly aesthetic but...).
As a final word though, my 6320 is incredibly temperamental - sometimes it'll boot, sometimes it won't. Don't ask me why as I've stripped it down many times and drawn a blank on every occasion. At the end of the day though it just doesn't inspire me in the slightest, and my iMacs blow it out of the water performance wise - looks like we have another machine that'll do nothing but collect dust for a while.
Note: Given how truly awful (and temperamental) my 6320 was it's now been stripped down for parts. I desperately needed the power supply for a Performa 630 (who's own PSU had given up the ghost) and as I rate 68K Macs above PowerMacs I wasn't too difficult a decision to make. I have kept the motherboard though so if it's ever needed I can pop it into the Performa 630 and away we go!