Everything I've tried on their menu has been excellent. They get ridiculously busy during lunch, so make sure you get there by 11:30 if you don't want an hour long wait.
After trying almost everything on their menu, I keep coming back to Garprow Pork Lad Kao. For around $9, this dish can't be beat. It has flavorful meat, rice, egg and some greens. The steamed dumplings make for an excellent appetizer, and the dipping sauce they serve with the dumplings is very well done.
My only gripe with this place is the inconsistency in their 1-10 spice scale. A 9 tastes like 6 one day and 8 the other. I just gave up and started ordering 10. Maybe I should try 'Thai Hot', but I don't think my colleagues will appreciate that ;)