I never touched a real PenPoint device, sadly. I never got to use a real NeXT cube -- they were formidably expensive over on my side of the Atlantic, the price of a _high end_ new car before I could afford a car at all.
I own an original copy of NeXTstep with manuals and have run it inside Previous, but it's not the same.
Mac OS X of course gets one the underpinnings of NeXTstep, but the UI has gotten kind of weird since 10.6.8 which was the last version I used regularly, making me wish that there was a "No iPad influence" checkbox for the UI.
That said, I'm glad to still be able to run Macromedia FreeHand/MX, and of course, modern hardware is just magical in terms of processing power, esp. for 3D.... but the way styluses have been crippled in Windows since Fall Creator's Update makes me a little angry every time I have to toggle stylus behaviour when switching apps (I actually leave the Settings app open) --- at least Firefox has a checkbox for disabling a stylus scrolling....
I played with a 30something friend's brand new ReMarkable a few years ago. I was torn between tears and rage. It is so miserable and dumb and primitive. I own 2 Newtons. The poor guy was shocked and baffled by my reaction.
Yes, I agree, Snow Leopard was peak OS X. Riccardo Mori wrote eloquently about this:
If I had managed to snag an Axiotron ModBook, I'd almost certainly still be using it w/ Snow Leopard.