I'll note that my favorite keyboard to type on, out of all keyboards I've typed on in the world, is IBM Model M p/n 1391401, s/n 0126050, manufactured 1993-06-03 by IBM.
There's definitely a wide variance in typing feel between keyboards. My Unicomp's typing feel feels... gravelly, yet lighter? I'm not sure how to describe it. It's definitely different, but I still like it - a lot - so it's my second favorite keyboard, and being USB, with 104 keys, and a TrackPoint, it's the one I use the most.
I definitely feel that the earlier keyboards have the best feel, though - but part of that could be break-in. These keyboards definitely have a break-in period... (It took a few days of typing with my EnduraPro before I felt comfortable with it.) Both my 1993 and my 1991 are very, very nice. (And, the 1991 was just as nice as the 1993 before it got a bit of rust on the springs.) The Lexmark boards I have... I hate my M13. Then again, I think that's the fault of the idiots that refurbished it. The parts board, I didn't type on much, but I didn't find it bad, but certainly not excellent.