All the same, LA not only has a higher expectation of the club scene and nightlife, but probably also deals with more of that sort of tourism and therefore makes it readily available. I personally have always enjoyed the Santa Monica area for a tame but always interesting nightlife.
It probably depends on what you're looking for, but I would hazard a guess and say LA has anything you want, unless you're really looking for a unique experience when you go out, in which case SF will always keep you guessing.
There are plenty of clubs in S.F. and plenty of clubs in LA. They're both culture rich cities.
What are some of the other considerations that you're tossing around?
Let me know, if I can assist. Best,