I'll simply add that you would not shoot at 200mm unless you had to. It's better to be closer. So if you know you need 200 that's what you need. But you wouldn't want to be back further simply because you had a longer lens.

But sometime with a tall, formal stage you have to be back to not shoot too much up at the performers.

You don't want it, but if I HAD TO shoot performers with only one lens, it would be the 70-200 2.8 IS.

The 200.2.8 is extremely nice, however, it was too long for me on a 1.6 crop. I would go with the faster aperture ... 135/2 wins