Blue Agave is perfect for what it is. It's a BAR folks....that just so happens to have an area with tables. If I wanted to go eat good Mexican food, this would be low on my list.
I happen to almost live across the street from it, and it serves its purpose as a great neighborhood bar to chill with friends at and have a few beers. As a restaurant....not so much. Food is just typical cantina type food, so don't expect much there...nothing to rave about, and nothing to complain about. There are a few yummy things on the menu (the mexican pizza appetizer is pretty good) but I mainly just go to drink. Their free chips and salsa and a cold 20oz Dos Equis are all I need!
They have lots of late night specials each day of the week, in addition to their normal happy hour (which includes half priced appy's and cheap 20oz beers). After 11 they have their late night menu, which is dirt cheap and has a few good things to eat on there (even if they weren't good, you can't really complain because of how cheap they are!)
The whole atmosphere is very laid back and friendly, nothing's better than just having a few beers with a friend out on the patio late at night, shootin' the shit about life.