I just switched from the Tekin RS ESC in my 1/12th to the Viper VTX1. Both are great ESCs but the VTX1 is smoother on the throttle and doesn't need a voltage booster for the receiver. Even though the specs say differently they are both identical in size. I put mine back to back to check. The aluminum heat sink case is really nice but is also the ESCs only real drawback...the weight. The next closest in small size that does not need a voltage booster or RX pack is the LRP SXX. The Hobbywing and Speed Passion ESCs also work well but are pretty big.