Well, I have to be impressed with the person first. Music comes second with me.
Out of all the concerts I've been to, those 3 have the best shows, so that is a large factor in it. Though Janet's last tour sucked ass.

This is why I don't like people that I used to love, like Madonna, she blows live now.
I wasn't all that impressed with Gaga.
But if I haven't had the chance to see someone live then I really don't judge too much. That is my main decider really.