The Apple II was the defacto 8-bit machine of choice for most of the North American developers, when looking at the collected anecdotes(Origin, Interplay, SSI and many independents like Jordan Mechner and the team that would form id software were all using them). Becky Heineman had a video where she explained why it was so much better than the C64 and most other options - the I/O and expansion potential was just a lot better on the Apple II architecture, and if you stepped up to the IIGS when that came around you also got some backwards compatibility with more CPU horsepower. Besides displays, the support for multi-disk systems was pretty good, and you could kit out the system to work with a generous amount of RAM and storage for the time. The competing Atari 8-bits also had good expansion capability through the SIO bus and dual cartridge slots which showed some very progressive design, but their potential went mostly neglected by Atari corporate at the time.
The C64 was a budget games machine at heart and didn't have the same kind of hardware support, but its reference manuals are famous for being a great introduction to computing. For many of the beginning bedroom coders this may have made all the difference.
The C64 was a budget games machine at heart and didn't have the same kind of hardware support, but its reference manuals are famous for being a great introduction to computing. For many of the beginning bedroom coders this may have made all the difference.