yeah, the brakes can be a bit touchy, but if you reduce the break power in programming, it is much smoother.
Don't forget, the 125B is technically a 1/10 scale ESC, much like the MM. So using it in a MT/truggy/buggy, it will work it harder. Doing the "internal mod" (despite the loss of a warranty) and adding a heatsink does wonders. Also, adding a couple extra caps helps a lot too...