Weeeeeelllllllllll, I used to LIVE in the Mission (tra la la!), and I happen to think Rancho Bravo is good. I'd say it's as good as my old favorite taqueria on Mission Street (which ended up, after much walking and biking around for experimentation, being the one geographically closest to my apartment—and yes, sure, I am lazy, but the further away ones just didn't ever seem THAT much better).
Damn it, I'm going to Rancho Bravo right now. Do I have Stockholm syndrome?! Let's poll!