Don't forget though that NeXTSTEP was also running on workstation-class hardware and priced accordingly (~$6500), vs. Windows running on late 80s commodity PCs (probably ~$1500-$2000) with lesser specs. For that kind of cost difference NeXTSTEP had better have looked and performed better.

A better comparison would be the Motif/CDE GUI that commercial Unix workstations were using at the time on workstation-class hardware. I think NeXTSTEP still wins on style, particularly since X desktops were a garish mix of raw X, Xt toolkit and Motif apps all coexisting.

Bill Gates was so worried about Steve & NeXT that Windows 95—often criticized as ripping off MacOS—is a much more direct ripoff of NeXTSTEP.

There’s the technology, and then there’s style. And stylish NeXTSTEP is…

That's a terrible comparison. Windows 2.x ran on much cheaper and weaker hardware. It required only 512KB of RAM and ran comfortably in 1MB while the smallest amount Next computers came with was 8MB.