I've ridden DH for two seasons with Avid mechanicals on my Bullit. They are FAR better than the HMX I had on my trailbike in terms of power, adjustment, etc. I have been pleased with the performance, but make no mistake, they are not the same as the "one finger on the lever" feel of modulation and power you get with hydraulics. It does depend on setup, 8" rotors are a must, and good cables, pads and levers will improve performance, but they are just not as powerful or as dependable as a good hydro. For the price, they are hard to beat, and work very well. Mine are going over to my new SS, and will be replaced by some Juicy 7s. It really depends on what you are looking for. If you freeride and plan to ride occasional DH, then go for it. People can (and do) race with them, but if you are planning on competitively racing or riding a lot of DH, hydraulic is the best way to go.