G4 vs. G3

[Michael J Flaherty]

I'm curious about the usefulness of AltiVec in Linux.  I'm about to buy 
another G3 (or G4) card for this 7300 (w/Nexus 128 and ATA100 card already).  
Looks like a G4/450 will cost about $100 more than a G3/500.  

Is it worth the extra money ?  I've noticed that AltiVec support is an option 
that can be compiled into the kernel, so I'd like to know exactly how much 
difference it makes in reality.  When and how is it useful in Linux ?  Does 
it make as much difference as it supposedly does with OS X ?  

I'm leaning towards just getting a G3, although the G4 would, I suppose, be 
better if I want to play with OS X on this machine.  If Linux also runs 
significantly better on G4's, then I'll swallow hard and go for it.  Sorry if 
this has been covered before.

TIA for any advice, 

MJF