Mac G5 pro still relevant?

I like the deal. The only issue I have is that the G5 can't use the modern Mac operating systems. You might need to upgrade memory if you do decide to get it, which is usually cheap for older Macs
 
I wouldn't do it, the G5s are ridiculously slow compared to the newer systems. You won't be able to use a lot of plugins and other software. Make sure your interface driver is compatible as well.. Even buying a used Mac Pro 1,1 is no good idea because even the low-end Mac Pro 2010 outperforms the high-end model from the first generation. The Ghz-number may not be (a lot) more but the performance increased drastically. Depending on the specs your current PC is likely to be a lot faster.
 
My PC is a Core 2 Duo 2.2 Ghz w/4 gigs of RAM. I decided to pass on the deal... I'll save my money for a newer Intel based Mac.
 
Don't buy a computer system that's that old. Apple changed to intel platform 5 years ago.


(The only reason why somebody should buy it is: You need to stay compatible with old standards, because you have backups you want have access to.)