I had another odd issue with mine, I have the aluminum pulley that Performance Bike sells... it worked fine with my old Shimano chain but when I replaced it a couple of weeks later with a KMC chain I found that the chain started slipping off of the bottom pulley while in the extreme cross-chain gears. Obviously, I don't ride in that gearing, but it was never an issue until I had that chain and pulley combo and I'll probably switch back to the plastic pulley because of it. I'll experiment for a while first and see what happens. It's probably a non-issue with a double crank but a potential problem with a triple.

The noise isn't terrible, but it is noticeably louder (especially in the stand). You can block it out while riding.