I, and a number of those I ride with, have used Avid mechanical disc brakes on our trail bikes - an Ellsworth ISIS, Joker 1.5, and a few ID's; a Santa Cruz Superlight; a Chumba Wumba; a Titus Racer X 100, etc - for some time. We've all had excellent reliability, no maintenance/service problems, and very good performance. Using Avid's Straight-Jackets and their disc brake recommended levers vastly improves braking effectiveness, making them close to hydraulics. The lighter weight, lower cost, and very easy set-up are also pluses. It's important to note we all use "fat" tires - Conti 2.3's or Schwalbe 2.4's - which likely helps braking efficiency. Regardless, keep the system clean and you'll be very satisfied with them.