The SS2 is practically identical to the IPX, only in a pizza box case, so you can fit two hard drives in it. It has 16 hardware contexts that give it an ever so slight edge over the IPX, which only has eight.
OK, so I installed SunOS4 on it just so I'd be able to play with NeWS, and Xnews segfaults when I start it. Grmbl.
Oh, but it makes a nice monitor stand, of course! The IPX's lunchbox case is smaller than the footprint of my monitor, but the SS2's pizza box is just right.
This one was given to a very dear friend who wanted to reminisce about the time she learnt Unix on such a machine.