I've been to the Big Bang a few times, always on a Fri or Sat night. Each time has been great. The dueling pianos are fun to hear and go back and forth. The players do an excellent job of getting the crowd going. Each player provides his/her own personality when playing.
The drinks are reasonable and you're served pretty quick. There are some tubs full of bottled beer scattered along the floor if you don't want to wait at the bar..
The only drag is that with the music going on, it can be very hard to hear someone talking with you.