I train at alliance training center, down in chula vista and i'm happy there. good standup, if u go to the early to midday classes it's relatively small so the trainers can correct your technique. offers variety of classes. friendly staff.
depends on where you want to train though. if you're training in escondido maybe it'd be worth it to go to temecula to train at team quest. in the college area (around sdsu) sdundisputed is good. in the pb area there's throwdown elite training center. lots of places to go.
use to train at the boxing club, it was ok. lots of ppl in the classes so the trainer never really got to correct u since so many ppl were there. anyways... those are a few i'd recommend.