I love piano bars... I can't say that I've had a bad time ANYTIME I've been to one, but the atmosphere at The Big Bang might have been my least favorite out of the ones I've been to. We went on a Friday night and it was beyond crowded... we couldn't get anywhere near the pianos. Heck, it was a LOOOONG wait to get into the bathroom. And, once we did get into the bathroom, we found out that there was only one usable stall because there were college girls puking in the other stalls- guess that's a hazard of going out around ASU.
They did have good drink deals and the piano players were great. I'd like to go again, but probably not on a Friday or Saturday night.