Your max head speed is limited by the rating of your blades. The "standard" woodies and CF ones that came with my SE were both labled as 2400rpm max on the package. I've read about people going up to 2800rpm and beyond for 3D. The faster you spin them, the sharper the response from the controls.

So this is another advantage of using governor mode, you can run your blades to their limit with much lower risk of over stressing them.