Same with the canti's on my Diamondback. The noise gets irritating in traffic, but it clears geese, people, and other animals out of your way like you wouldn't believe.

I think the problem in my case is that the canti posts attempt to rotate the pads to be flat when against the rims, but if you're feathering the brakes, the tail end is contacting first, causing the squeal. So you need to really toe the pads in to get around that.