Depends on many factors, including time/day of week, how many tickets I'm buying, length of trip, nature of the flight, etc. But it's pretty rare I end up at SJC. I don't care for OAK either, but I prefer it over SJC since it's closer to the City.
We did take BA on award tickets back to SJC a month ago when SFO awards were unavailable. I have to say the CBP experience at SJC was unfortunate.