These do provide the MOST braking power available in the extreme braking category, highly recommended. Do your research. A set of these retails for $600 plus tax.
I have one set of these, and some spare calipers. The brake sets are $225 ea, and the calipers are $99 ea, with purchase of both sides.
Since they are mineral oil brakes, I personally recommend coupling these calipers with a shimano servo wave handle ( I have several shimano handle options from Deore to XTR ), which is what I did with one set of calipers. Ridiculous stopping power with no hand fatigue or arm pump. They also retain the shimano ramp up feel with a bit more modulation.
A full shimano-maven set new is $495 total for front and rear.
As for these full sram brakesets,
Features
18 and 19.5-millimeter pistons for best-in-class power
Swinglink for signature SRAM lever feel
Stiff 4-piston caliper with best heat management and easier bolt access
Organic pads come standard for the best modulation and the quietest ride
Stealth lever architecture for a sleeker, more modern ride
Mineral Oil for low maintenance and performance
Designed for use with Maxima Mineral Brake Oil only
Ultimate worthy polished Lever body and Titanium hardware
Contact Point Adjust and tool-free Reach Adjust
I-10 and Chandler Blvd
See the "more ads by this user" link above for more Mountain Bike parts and brakes