Tallahasee Rider wrote a review of Shimano XTR BR-987 Race Brake on September 1, 2014
Familiarity: I've used it several times
So far I've been very disappointed with these brakes. I replaced my Shimano XT BL-M785 with these brakes and upgraded my wife's brakes with the XTs. Unfortunately the XTRs have a lot less power, I'm constantly over shooting corners and my hands go numb from squeezing the levers so hard. I had my fingers crossed the pads needed an extra long time to wear in but that was not the case. I did a lot of trouble shooting and bled the brakes twice. I started by swapping out the pads with pads that were on brakes that worked and this didn't help. I have 4 sets of Shimano brakes, 2 XT BL-M785's and an older Shimano XTR BR-985, all of these have Shimano resin pads paired with either XT or XTR rotors and all three work great.
The levers on my new 987s feel great and are not spongy, it doesn't seem possible Shimano would upgrade their brakes to weigh less yet sacrifice power. I can see having one defective brake but not a pair of bad brakes. I'm stumped, anybody have any suggestions before I return these brakes?