They top out at 15 mph in SF. I wish they went faster. I am a cyclist and usually maintain close to 20 mph (not counting lights). It's kind of maddening not to be able to go 20 or 25 on them.
I've been an iPhone user for a decade and am a huge Apple fanboy, but even with that bias, I have to say this is a load of crap. Apple has been adding loads of undeletable bloat since forever. they only really let you start deleting the Apple pre-installed apps very recently. I still have a folder on my devices called "iCrap."