I always thought the 3" disk was mechanically superior to the 3.5" one.
Pity more manufacturers didn't use it.
Well, there was no crappy flimsy shutter to get ripped off. The
single-sided drives used a belt-drive mechanism (the only double-sided
_Amstrad_ used belt-driven drives, but the Hitachi drives I used (both
single and double head) were direct-drive.
-tony