I have frequented Rula Bula for a few years now and it is hard to pin point just one thing that keeps me coming back. The food is great as is the service and I love the authentic feel of this Irish pub with it's odd ball, mismatched tables and Guinness decor.
I typically order the corned beef sandwich on rye and it is sublime. The three cheese grilled cheese sandwich is also very, very good. While some feel that the beer selection leaves a lot to be desired I have never really seen it as a problem.
My only complaints about this establishment are their lack of a "true" happy hour and the crowd that sometimes fills it's patio. On a few occasions the patio bar has been occupied by some of the scummy mill crowd which is a disappointment as this is normally a great place.
I would highly recommend Rula Bula to anyone looking for some great Irish grub at a reasonable price.