It's a dive bar, and a thumpin good one. Service is friendly (provided you don't piss anyone off), food is good for the type of venue and deals are plentiful ($5 daily sandwich specials, half-price appetizers for a decent stretch of time, 4-6 if I'm not mistaken). The clientele is as much a draw as anything else; if you don't go in with a friend, you'll leave with several new ones.
A fine (if cramped) front patio only adds to the charm. It's a place of character, and you'll love coming in (especially when Donna is working, the day shift every weekday).