Things are more clear as to what model you're getting and the specs these days. I had a terrible experience with my beige G3. It was catch 22 situtation too, I'd be kicking myself even if I'd got a B & W G3 only to see the G4 come out later in the year.
There was never a 300Mhz Beige Desktop in the UK officially until the 3rd revision of the logic board. I bought a refurb Beige G3 instead of a blue & White G3 because it was supposed to handle slave support on the hard drives, have an ATI Rage Pro+ (which I spent extra on maxing out the VRAM), a 1Mb L2 cache and be able to use go up to 768Mb of RAM.
The worst thing was the CDR of OS 8 it came with, I expected OS 8.6 like the Beige G3 shipped with at the time. It really put me off Maczone for life after that. They were bought out by Cancom so I guess they're a good company to buy stuff from again now but I was so annoyed when I found out I'd got a model from 1997!!!
It was a Rev A model, I was gutted. Being my first powermac and a lot more useful to me than the Atari STE it replaced, I just bared with it. I wasn't even aware I had an older model until I got online and found out about the full spec of the system from sites like Xlr8yourmac. By then there was no way I could have returned it. I'm sure the fact it was in full working order made it impossible to return anyway. It wasn't broken.
The Diamondscan 70 monitor I got with it blew up about 2 months ago, the CD ROM packed up over 2 years ago and I had to completely reformat the internal system drive once because it couldn't see it on start up. Overall, my Mac experience has been VERY expensive and VERY disappointing.
Especially seeing as if I want to continue to use the fairly expensive hardware I've bought for it, I absolutely have to get a dual G4 for my next mac because I simply can't afford to replace PCI cards with firewire or USB equivelents just because apple havn't had the sense to put standard PCI slots on the G5 for backwards compatability. I can't even try OS X till then either because my Mac isn't supported.