You should try Marin County Transit--you could walk faster. When I worked on SF--I quickly bought three beater bikes and chained them up. They were so crappy no one stole them. I chained them in strategic spots around town and used them. This was 10 years ago, maybe the thieves have gotten desperate?
With the exception of one route (the 35 serving the Canal Area, which has very heavy passenger loads), if I show up at a bus stop in Marin County 5 minutes before the time indicated in the schedule and wait for 10 minutes, the probability that the bus will fail to come some time in those 10 minutes is less than 1 percent. On non-rainy days, the probability goes down to about 0.2 percent.
In contrast, when I lived in SF in the late 80s and early 90s, the probability was about 50% (and higher than that in the Mission District). There was no sense in consulting the timetable: the best strategy was to go to a bus stop that has buses that go where I want and wait an indeterminate amount of time. Sometimes it would take 3 hours for a bus to come, then 3 or 4 buses would show up in a 3-minute interval. This during non-commute hour when the (useless) official timetable has the buses coming at regular intervals.
Marin County resident since 1995; car-less most of that time.
When the traffic along a route is uncongested, Marin Transit buses will wait at some stops so as to avoid leaving any stop before the time printed in the schedule. Most of these waits are only a few minutes. Are these waits at bus stops what you refer to with your "you could walk faster"? Well, if so, it still seems to me like the best way to do it, since the bus's not going as fast as it could at times of less traffic congestion than usual is made up for by the rider's having to wait less time at the stop. And except for the ones on Route 35 and Route 17 (the ones without upholstered seats, that is) the buses are much more comfortable than Muni's buses.