I was in Pittsburgh over the weekend for a wedding and stayed at the Westin. Bills Bar and Burger is the hotel bar/restaurant.
Pros - Service was great. Every employee was attentive and easy going. Vincent the bartender, GO TO HIM! There was a female bartender as well. I can't remember her name, but she was fantastic as well. $2 happy hour drink specials. SERIOUSLY AMAZING! They serve food until midnight I believe. I had an order of fries. Fresh and crispy!
Cons - They close too early, but not their choice. After several drinks you can get lost trying to get to the restrooms. That's it. No other complaints from me.