Max Motor Speed

I was wondering what everyone considered the max speed for their motors. I have heard that 80% of 127 is the best speed because anything after that generates unnecessary heat. Thoughts?

this is somewhat true, if you were to graph the given value vs motor rpm, you would notice that the rpm dies off at around 100.

With testing with trueSpeed, and with testing you learn that everything above 85 power gives off equal RPM to 127. The torque does change as @PixelToast can explain better than I can, but the RPM is the same.