When I started my CNC (V1.0), I was using 1000 line encoders (4000 quadrature) and the only problem was the unit was slow due to computer speed limitations.
In my latest setup, I am using 500 line encoders and with a new power supply, am getting 120 IPM rapids on my mill/drill (X and Y axis only). With properly tuned drivers, the following error is not a problem. Matter of fact, I like the idea of a tight system.
Would I use Geckos again. You bet your sweet bipie :})