Food is exceptional. It's a bit of a drive for me, coming from the NW of Calgary, but the food is easily worth the drive, and the wait. The staff is always polite, and if you're lucky the chef/owner, Jimmy, will come say hello, as he often does with his guests.
With the best atmosphere, tastiest food, gracious owners/hosts, Nawab is easily the best authentic Indian restaurant in Calgary. Notable: The garlic nann bread is beyond belief.