We've been to Ruchi's twice now, and my wife and I are both big fans. I used to go to Udupi years ago when I worked near there, and Ruchi's compares very favorably. The weekend buffet is 12 bucks, a bargain for such a variety of tasty food.
There are lots of curries and other dishes, both vegetarian and vegan. My favorite on our last visit with a very spicy mushroom curry. There's a wide range of flavors, more so than a lot of your standard Indian buffet places I think.
Dosas are part of the buffet service, served crispy and hot at your table. We were eating them unadorned, so the owner came over with the appropriate sauces and showed us how to dress them properly. I also had a lentil donut I'd stopped eating, and he told me to put the sauces on it as well, and that made all the difference. I always wondered why people wanted to eat those things. Now I know.