The Oryx brakes have decent stopping power, but I had a lot of problems with grit contaminating the pivots. The grit made the brakes work poorly (kind of a gritty feel to the braking action), and once, after riding in salty conditions, the rear brakes actually seized up from corrosion in the pivots.
I have since replaced my front Oryx brakes with Pauls, and have been really happy with them. They have a lot of stopping power, and the mechanism is sealed with o-rings, so I don't have to worry about contamination. I still use the Oryx brakes on the rear; it just doesn't make sense to spring for the pauls because I almost never use my rear brake.
I have Shimano BR-550s on another bike and I prefer those to the Oryx. They have better seals, and stopping power is a little better.
Regardless of which brakes you get, be sure to get kool stop pads. I prefer the salmon MTN flavor.
Edit: I am an all weather commuter, so in my case the Oryx brakes are operating in extreme conditions. You might not have issues with grit and corrosion if you don't ride much in the rain/salt/sand.
Last edited by matthew_deaner; 02-17-08 at 06:18 PM.