In reply to momuscles69:
Hi, I have just done two weeks in the Alps in Phantom Ultras and couldn't recommend them highly enough. Really comfy, warm enough and not at all cumbersome. If you are planning to do winter alpine though, maybe don't go for something this lightweight. In terms of fit, they should be almost identical to the guides, as they are the same boot with a thicker sole and more insulation. Hope this helps