If you're using clear pads on a chrome rim, it will almost always squeek until you build up a film on the sides of the rim. If you don't dig it, switch to black pads. Black Odyssey Ghost pads are awesome. If you're using a black rim, it will go away eventually.
I bought a brand new Evo 2.5 because a guy was selling one cheap. I've had nothing but problems with it. I THINK he sent the wrong springs with it, though. But when you get the brake set up, it just jams up and gets stuck. I've tried to set it up twice. On two different set-ups. Same thing. So I ended up putting my original Evo back on until I can order some springs from Odyssey. I love Odyssey parts. I probably have $3500 or more of their stuff in my parts collection. I'm a brake tuning autist and I can't see them releasing a POS part in this day and age...so I'm convinced that the guy sent the wrong springs / hardware with it.
What about the angle of the cable entering the brake arm? I was getting a grinding noise from that. Sounding like metal crunching / grinding. I grabbed where the brake cable meets the arms and moved it around..then tweaked it to make sure everything was centered. A TINY bit of lithium grease or a drop of oil helps when applied where the actual cable slides on the arm (on the cable side of the brake)..
Also, the only times I've ever heard / felt that grinding / crunching noise was with Evo brakes. When they are set up on the front. They seem to do that when the cable isn't centered. Meaning, the cable itself is just a mm or so off from being centered thrugh the brake arms for some reason. And the only real difference with the 2.5 is the room for a fat tire. So I'm sure they still have that issue from time to time.