I like 'em! Yes, the gocars are overpriced, but for many the open air novelty of it all will add enough entertainment value to justify the cost.

By the way, regardless of the time of year, have lots of clothing layers available if you plan on renting one of these. Low 50s, foggy and windy could make for a chilly experience. Then again, you might get a sunny, calm day in the 70s.

Edited to add my standard SF advice: if you are in reasonably good shape, rent a bike. There's no better way to tour SF, in my view.

http://www.blazingsaddles.com/