There are certainly lighter brakes available, however power is a different matter (not saying m4s are the most powerful brake on the market as I’m sure there are other equally or more powerful). I think that often that grab/bite is mistaken for power, you get a jolt therefore a brake must have lots of power. As I’ve posted before consider the example of car brakes. Our golf has servo assisted brakes, which give the impression of loads of power very quickly (as the servo bites), my elise on the other hand has way more powerful brakes, but is not servo assisted so does not have that bite/grab feeling. It does generate a lot more retardation though when you press the pedal further. To me the m4 is like the elise brakes, with plenty of modulation and power on tap if you want it. The shimano brakes are more like old hayes 9’s and the golf. The power is there all at once with little modulation.
+1
My new XT’s are whiplash induceingly powerfull at first, but if you pull the lever to the bar, even with 200/180 rotors, they don’t actualy lock up (of hold me still) on tarmac (at low speed, decending a 1in3 hill with my weight back).
Whereas I can lock my X2’s up doing the same test, and they’re the older non-EVO versions with mini levers which got panned in reviews.
I’ve got shimano brakes, but only as they’re half the price of HOPE, if HOPEs turn up for a good price second hand I buy them as even if they’re buggered, they’ll be easy to get new seals in and back to normal.