I have both, and the Mx-1 doesn't even compare. Mx-1's work okay if they're adjusted right, and if you have a big rotor, but they constantly need adjustment. And you have to carry around allan keys to do it. BB7's are far easier to adjust. BB7's have more power than the Mx-1s as well. Mx-1's arn't as durable either, they will snap after a while, especially with big rotors.
Get the Bb7.