Tekin is a really good combo and so is castle. I like castle because there reliable and cheaper. But here why tekin is loved and valued so much to racers. Because there sensored or sensorless making them much more smooth. Also Tekings dont clog off throttle like castle. Clogging the the magnet grabbing inside the can trying to in a sense worke as brakes on a car slowing without touching brke though. The tekin off throttle is free and coast alot more smoother. I still take caslte over it because the tunning at the track is so much easier and there one of the most reliable systems on the market today. The mambas also can take abuse over tekin more. Tekins get tempermental if over heated and a mamba will run but its impotant to temp them and run safe gearing. I never let my esc or motor top 200 degrees f. Thats scary to me. some say 220 like a engine on nitro is fine but i disagree.