I am hoping to get into winter climbing this year by taking an avy class and a winter climbing class, but need to upgrade my insulation jacket. I am looking for a synthetic insulation jacket for climbing in the Olympics / Cascades in the winter / spring. I have read many previous posts on the DAS parka, but wanted to know if people had much experience with the Arcteryx Dually Belay jacket, Montbell Flatiron, or Rab Belay jacket. Thanks