Yeah, I saw the Momentum at a Future shop and was surprised to see it's $400 here. I don't get it. The CDN and US dollars are almost at par. Plus Senn launched the Amperior at $350 - same as the US. I also got mine from razordogdeals and am content with the price.
At $400 plus taxes, the Momentum becomes harder to recommend. I don't think it should be more expensive than the Amperior.