retrocomputing

I’m curious about picking up a mid to late 90’s Sparc desktop/server. Just to keep rounding out my retro collection. I’m pretty much good on vintage macs and PCs and want to get something similar to the servers I used to bounce around back in the day.

Any models in particular that are great or to avoid? I’m thinking SparcStation or maybe an ultra 1-5. What do I need to look for? Obviously the drive will need to be replaced and I’ll want Ethernet. But anything else to be aware of? I see some eBay listings call out good or bad nvram too.