When I used to work in downtown Phoenix, I would sometimes make the drive out to 44th and Indian School just to get me some fish tacos. The staff is pretty friendly here, it's a large space with a great patio, and clean!
While I have a wealth of Mexican to choose from in AZ, I really do love Rubios, chain or not. I've been going to them all over the Valley since they first started opening. Solid menu, cheap, and satisfying. Love their salsa bar. $1.50 fish tacos, burros under $5, mmmmmm.