I am a bit perplexed by the reviews proclaiming that Andy's does not feel like a hotel bar. It is a fairly typical hotel bar that you would expect to find in a modern/boutique hotel. Andy's is right off of the main lobby and extremely bright. Andy's could actually stand to dim the lights a bit, to be quite honest.
I have no idea what the cocktail scene is like in Pittsburgh, but I don't think I would opt for Andy's as a destination if I were not staying at the Fairmont.