> Also, they got more capacity, but did they also get at least the same speed and reliability?

1541 was horribly slow because the marketing people wanted it to be backwards compatible with VIC-20, and the serial protocol used by the VIC-20 was very slow because of a timing bug found at the last minute. It was possible to multiply the default speed by an order of magnitude or more using custom firmware, but stock software was almost slower than using a cassette tape.