I think you are giving them more credit than they deserve. Besides the high resolution screen the A3000 of it's day had more power. I used admin NeXT machines, the original CUBE was a 68030 machine with a 56001 DSP.. There were also later color "Pizza Box" versions and they move to INTEL white when they moved their OS to run on the super powerful 80486 chipset..
If you want the NeXT UI, you can get a decendent of it, in Mac OSX, or you can go get the freely available openStep which runs on many platforms. Most NeXT applications were designed to be portable to OpenStep.. The UI was ahead of it's time, but not by much. and the Mach kernel was pretty cool for a Unix type box.
You should check out
http://www.gnustep.org/http://en.wikipedia.org/wiki/OPENSTEP
