[billbo911]

Originally Posted by Andrew Schreiber

I should have been more clear, I dont like them for sensing position of a system that has slip. My issue with them was that our drive system had this knack for accelerating quickly and the wheels slipped occasionally...

I know this is a little off topic, but I still believe it is useful information.
We experienced the exact same issue last season. Our solution was to add a very simple function that would limit the acceleration/deceleration. It was tunable for each to allow for better response. This allowed for maximum acceleration without slippage. With a little tuning, it performed quite well. We were able position the robot during autonomous mode quite accurately.

The slipping issue would have been there as well if we used encoders instead of GTS's. The same solution will work for either sensor. The biggest issue with GTS's vs. encoders is that GTS's, in general, really do not give you direction. You need to derive that from some other source, like the drive signal (PWM) for instance.