Very confusing stuff: I'm in the same position as you, got my eyes out for a NL Rack 3 personally. The very general consensus (that varies wildly per personal accounts of course) basically get 'better' as you go 1-4, but 1 or 2 is the more 'classic' NL sound, with 2 being much more versatile than 1. 3 and 4 are definitely still NLs but the guts started to get a little too good (remembering that of course Clavia are trying to emulate stuff like piano and analog synths generally with the NLs) for electronic weirdness and the sounds got slightly more stale or normal or something? I'm still not 100% sure as I'm basing all of this on Gearslutz and other places talking and posting some examples and such. 2, 2x & 3 are all pretty much the same but the UI on 3 is much better basically, hence why I'm interested in that one. The forum-wankerTM consensus is that the 2 or 2x is 'the best' basically, still a 'raw' sound whatever that means. 1 is too constrained, 4 is too 'good' and normcore. There are expansion cards on the first two, I think, that allow for more polyphony and user save spots, I think?
No one even talks about the A1R even though it's basically the successor to the NL from my understanding.
Someone with more actual real knowledge and experience could probably be more useful as I'm probably just regurgitating what you've already heard Stick, but I'm honestly sorta hoping that the users here can come explain where I'm wrong or give their take on things. I'm pretty set on wanting a 3 but still not 100% sure and would listen to any reasoning why another is better....I'm honestly not totally sure I want one at all.