My girlfriend and I absolutely loved this place. We were in McLeod Ganj for about 4 days, and we came here about 5 times, despite only discovering it on the 2nd day we were there.
The staff are incredibly friendly (most of them do lots of community work too), the food is a pretty awesome, and very vegan friendly. In fact, it was probably the most vegan-friendly place we went to in North India. Pretty much everything in the menu is vegan, but you can get cheese/cow milk and normally that involves a little surcharge. Menu is varied, but everything was excellent. Their Burritos in particular were divine, and the ferderfer was by a long way the best veggie burger we had in India (most indian veggie burgers are potato based - whereas this one had a real mix of nuts, lentils and seeds and differetn vegetables).
Smoothies were fantastic also. In particular, the simple Sadhu and the date-shakes were awesome. Never got there for breakfast, but can only imagine what the scambled tofu tased like in the morning.
Khana Nirvana is also an excellent place to hang out. It is popular with ex-pats volunteering at NGOs, there are lots of open-mic nights (with great performances), there were film nights and speaker nights too.
The only problem with this place is that is a bit hard to spot. It's up a load of stairs down temple road at the south side of the main market. We never would have seen it if weren't looking for it (it was advertised in the lonely planet as having very good evening entertainment). There is also a bit of a large drain you need to hop over to get onto the stairs which is a little dangerous. Definitely worth the risk in my opinion though.
Cons: Bit hard to find