There are other Indian restaurants in the area where you can get somewhat better food (Punjab in Arlington, for example), but this is hands-down the best option in Somerville and the Porter Square area.
The service is friendly and solicitous (love the hot towel before the meal!), the food is very good, the prices are reasonable, and the convenient, Davis Square location is great. There's never a wait, either.
More people seem to be drawn to Diva, a block away, which has a trendier, more stylish ambiance. But the food is simply not as good there, and the service is often downright rude.
Namaskar is now our "go-to" place for Indian food.