Their "sabjiko" dishes appear to be all-vegan and the ones I've tried certainly are - also delicious. I often order online and always enjoy (particularly the Aloo Ra Rayo ko Sag [potato & greens] and the Tofu Ra Palung [tofu & spinach]).
I've only been inside the restaurant a few times and had good experiences - one of the workers I spoke with was very knowledgeable about veganism and was able to quickly tell me which dishes were vegan.
I have never tried the Indian options they have yet as I really like the Nepalese options (which are also less prevalent in Boston). Nepalese (at least the vegetable dishes) tend to be similar to Tibetan, but less oily, kind of like a vegetable stew with a spicy (often ginger-y) sauce, meant to be eaten with rice. It's vaguely similar to Indian also, but less onion focused and no pureed veggies (Nepalese has bigger pieces of vegetables) and a bit more watery and healthy-seeming.
I'd definitely recommend Yak & Yeti for trying some Nepalese vegan. They're good with takeout if you live nearby (I just always specify "no dairy" just to make sure they don't give me any sauces that might not be vegan).
Location wise, it's convenient for me in Medford. It's not particularly close to the subway, but isn't particularly far either (about 1-1.5 miles from Davis Sq).Pros: tasty vegan sabjiko entrees, friendly staff
Cons: vegan items are not marked on the menu, serves meat