It's a bit hard to put into words the difference between a bushing and bearing shaft, since it comes down to the feel of the steering. Basicly a bushing has a bit of drag resistance that causes an almost imperceptible sticking feeling going from one direction to the other, and has a bit of extra drag overall. A bearing on the other hand is perfectly free, and thus more sensitive and smooth especially around the steering center where the spring tension is at it's lightest. While both types of shaft will hold up indefinitely (we provide a lifetime warranty on both), most people who go from bushing to bearing tend to like the bearing best.
The bearing shaft is not available for all controller versions. Choose the appropriate version for your controller from the pull-down list. Click HERE if you are unsure which controller version you have. If your version is not listed, there is no bearing shaft available for your controller.