Hello,

> the SP machines are Ultra 5's.
> 
> however, i run many machines on NetBSD (many different platforms), so i 
> don't mind :)
If you don't need threads you'll probably be fine with NetBSD, but if you do need them you're in for all kinds of nastiness. Some of it is fixed ( didn't see a kernel panic or a deadlock for a while ) in -current but we still get apparently random SIGSEGV and SIGBUS from libpthread. Some threaded applications work just fine, some don't work at all or crash randomly. 
So if you want stable workhorses go with Solaris right now, maybe keep one U5 with NetBSD to play with, there's still a chance it will do what you need.

have fun
Michael