I was lucky, in the sense that I jumped from Z80 to 386/486/etc. Because Zilog was basically founded by ex-Intel staff the instruction-sets weren't too dissimilar.

I could never get my head round 6502-instructions (as a teenager). These days I guess my knowledge is largely obsolete as I stopped writing Intel assembly language around the time SSE came out. Still there are times when I decompile & patch binaries for fun, so it wasn't entirely wasted.

I had the same phasing ( MSX 2 (Z80) -> Amiga (68k) ), but because I spent a lot more time on the Z80 and programmed many games and demos back then, I never really got to like the 68k or Amiga chips, although I did a lot of dev on it as well.

My route was 6502 (Acorn System 1, PET, UK101 and C64) -> Intel x86 (In-house dev). I've actually not done any Z80.. but at least I have a board for it now!