Go Feigao, I've heard they're real good, and you cat do better for the price.

As for cogging, it's not as bad as everyone thinks. I thought my motor would stutter and lag and be jumpy, but neither of my Lehners are that way, especially not the 2800xl in my Ofna 9.5; that one is as smooth as can be and doesn't care if you peg the throttle from a standstill or from halfway. My Lehner 5300 is a bit worse, but I think that's the controller. Anyway, with most sensorless, you won't be able to hit full throttle instantly anyway, but instead by getting the vehicle moving, then roll the throttle to full. It takes more driver finesse, but isn't hard at all, you just gotta learn to do it right.