I've ordered it for mine. More for image/look really, I'll admit that.
No doubt they perform better. But it's certainly not a must have by a long way.
There's probably a lot of other things you would tick before you tick the M brakes.
330D M Sport Estoril Blue 19" + M Sport Brakes, Adaptive Suspension, HK Sound, HUD, Stop+Go, Vis Pack, New Pro Nav.