the gun pointed at the head of the universe
I've really only noticed bleed-through here and there, and on players that I was honestly going to kill anyway, it just made it two seconds or so quicker, which was nice; and when it's happened to me, likewise, I was done for anyway.
Maybe it's because I don't melee a lot that I don't see the annoying side of it, because with the TU, if I have your shields down I'm about to headshot you anyway, so I don't see the problem really.