Having moved to the 6502 from Z80 back in the day, I initially had that feeling too - what? Only 3 8-bit registers on the 6502? The Z-80 had an abundance which

Having moved to the 6502 from Z80 back in the day, I initially had that feeling too - what? Only 3 8-bit registers on the 6502? The Z-80 had an abundance which is not trivial to describe (7 8-bit ones, 6 of which group into 3 16-bit pairs, an exchangeable shadow register file for them, and two additional 16-bit index registers); Z-80 also had block move instructions and other nice stuff that was missing from the bare bones 6502. And yet, the 6502 eventually comes out at least as useful with the indirect addressing and page-0 -- to the point that it often feels like you have 128 16-bit registers, or 256 8-bit registers, or any combination of those. Z80 is more high-level, but it comes at a cycle/instruction cost, and 6502 indirect indexing goes a very long way.