Hmmm here are some completely useless thoughts from me: my favourite brake I've used is Avid Elixir 1s. But.....
I think I may be the only person in the known MTB world who hasn't had problems* with them (mine must have been made mid week, definitely not on a Friday). They've been fantastic, great modulation and power. But....
Based on everyone's experience I wouldn't get them again; seems like I just purely lucked out.
*OK not 100% accurate. In the winter I bled the brakes -not because I needed to based on feel, but because the fluid in them must have been at least 5 years old. After much fiddling around, I had the brakes perfect, nary an errant air bubble in there..... But then came Spring and I took the bike out to find out within 5 minutes the brakes started to severely bind. I ended up letting some fluid out, and I was fine -my theory is that I bled them so well, then came Spring with warmer weather and the fluid expanded..... Anyway, back to the way they were now, so no problems!