I think battery buses have comprehensively won this one, to be honest. The biggest hydrogen bus fleet seems to be 35 vehicles; there are many BEV bus fleets in the hundreds and some in the thousands.
As a certified old person, I'm having trouble getting used to them. It is unnatural for a double-decker bus to pull up near-silently, and then move off smoothly when you get on. They are _supposed_ to vibrate violently and sound like they might explode at any moment; it's traditional.
(One of the bus route closest to me has a mix of fancy BEV buses and ancient diesel things from 2007, so I get an interesting selection. The other is mostly plugin hybrids, which are extra-disconcerting, as they're either silent or very noisy depending on mode.)
As a certified old person, I'm having trouble getting used to them. It is unnatural for a double-decker bus to pull up near-silently, and then move off smoothly when you get on. They are _supposed_ to vibrate violently and sound like they might explode at any moment; it's traditional.
(One of the bus route closest to me has a mix of fancy BEV buses and ancient diesel things from 2007, so I get an interesting selection. The other is mostly plugin hybrids, which are extra-disconcerting, as they're either silent or very noisy depending on mode.)