I won a 17.5 motor/esc Trakpower combo at a recent race I attended. I haven't used the setup much, but from playing with it one practice day.. ESC seems pretty smooth (probably couldn't even tell the difference between it and my Orion R10 pro). Don't like the fact that you cannot use a proigramming box or link to change settings- It all must be done via the esc.

The 17.5 motor wasn't blazing fast, but it got the job done.