The xl3100 is faster and more efficient than the the 9L, as well as weighing a couple ounces less. The Lehner motors also are rated for 65000 rpms vs 50000 rpms of the Feigao motors, so they can safely be pushed a little harder when it comes to cell counts. Personally, I like the Lehner motors (I am somewhat of a light weight buff), but the feigao motors work great as well (I also use the 8L in a truck).