While I learned programming with 6510, I agree that 68000 instruction set was much nicer and easier to read and learn. I would also chose 68000.

This said, 65XX on an early Commodore computers was extremely rewarding to use because there was no memory protection and you could write code altering video memory, mess with sprites, fonts, borders, interrupts, write self modifying code etc etc. 68000 assembly on Amiga was more safe and controlled.