Really people? Is this the same volcano I just saw out my hotel-room window about 12 times?
If you're walking around, fine, stop and take a peek. But really, I don't think it's necessary to go out of your way for it. We were walking by when it happened to go off, and my instinct was to get away from the crowds of people stopping to watch as quickly as possible.
Yes, there are flames. And smoke. And water. And brightly colored lights.
I guess it's just one of those things like everything else in Vegas that you should try to go see once.