Pros: The scenery, being a messenger here will prepare you for anything.
Cons: The hills, the roads, the wind.

San Francisco seems like the kind of city that would be good for just one kind of cyclist-the ones with a death wish. Anyone who's seen a Dirty Harry movie knows what those hills are like, and it's not just going up them that could prove problematic. That said, bike messengers use the city as a proving ground, and the city has done much in the past four years to become more bicycle friendly. There's still a lot of work to do, but the ride across the Golden Gate Bridge into Marin alone is worth the trip. Also worth noting, the first Critical Mass ride was held in San Francisco in 1992.