Rotor and similar chainrings are designed to help gear down your upstroke, and gear up your downstroke (where you make most of your power). They have come in and out of popularity since the early 80's with Shimano's BioPace rings. Some say they help, some say they don't. I have two friends that run them on their road bikes and they swear by them. They're both pretty fast so I tend to put stock in their opinions.

All chainrings have a bit of ellipse to them, which is why you have a spot in your pedal stroke that causes the chain to be more loose, then more tight again as the cranks spin. The rotors just accentuate this. You'll have to compensate for it when you put your rear wheel in the dropouts and, depending on how much of a difference in gear inches the rotor cranks give you, it may not work for your bike.

All in all, I'd probably steer away from them on a track bike, but would love to try them on a roadbike where you have a derailleur adjusting the tension.