This is the probably best Thai restaurant I have found in Pittsburgh - the Tofu Mussaman Curry is fantastic and the spring rolls are always worth it as well. Never had a bad meal here!
It's on the second floor of a building on Forbes Ave in the heart of Squirrel Hill, and if you get a seat near the big glass windows you get a nice view of the hustle and bustle below. It has a great ambience and the staff has always been friendly.
The reason I deduct a star - last time I was there with a friend who is also a vegetarian, we ordered a tofu pad thai and found a few small pieces of chicken in it. Probably an understandable mistake, but still sort of unnerving. The service and the food was otherwise great, so we didn't make a fuss about it.