Another feauture that has not been brought up for the sensored ESC's is "boost" or the ability to electronically tune the motors timing in realation to its RPM's thus increasing performance. Although alot of SC stock classes are banning this function it does allow you to extract a noticable increase in performance from a 17.5 or 13.5 brushless motor.

I too run Tekin, in fact they developed the first programable ESC WAAAAY back when. I have the RS model and it has been great, not to mention their customer service is fantastic.