I paid $70 for the tickets and, yes, I left early! Hell, I even gave up my spot at the front during the second half because at one point I almost passed out before Emperor went on from standing around in the same spot.
And, being that it was another 20 minutes, I don't think I missed too much.
No, I don't have any regrets about leaving early. It got me home at 1 a.m. and not after that.