Ian Pickard wrote an answer about Marmot Guides Hooded Down Jacket - Men's on January 6, 2012
I love my ama dablam. Realy warm and incredibly light. Packs down into its own pocket too if you want to stow it away in your pack. Sometimes i question its durability though. The shell is fairly thin and it could possibly rub thin under packstraps. Really big hood on it if you plan to use it with a helmet. I know the Ama Dablam is popular for mountainering to go under your hard shell. The Ama Dablam is 6oz lighter and 800 fill which means it will compress smaller but I don't think it has a DWR coating. 800 fill is going to beat 650 fill everytime. As a ski jacket I think the guides hoody wil suit you better for durability. For warmth and compressed size i would go for the Ama Dablam!