Ion is a great wind & light rain jacket. Definitely for the active sports of running, hi-tempo riding, & XC skiing. Don't try & sit in it at a December Chicago Bears game. I'm 5'10" & ~ 165lbs, it has a technical fit, but never feels restrictive. My Men's medium weighs 4oz. For those windy days or rides, its a very versatile piece when you choose to layer it w/ various weights of wicking base layer. I found mid 50's w/ capilene 2, 40s w/ capilene 3, & powerstretch for the 20-30s to work best for me. I know its cliche, but it really does work & keep the wind out w/ its tight weave. It moves body moisture well, haven't had condensate on the inside at all. Haven't had long enough for durability issues, but I wouldn't run into thorn & bramble patch with it, nor would I rock climb in it. Has a soft hand, drapes well, matte color (not shiny) packs into its chest pocket, tech fit eliminates need for waist cinch cord, has longer tail, has funky foam hood drawcord (keep wgt down?), hood rolls inward to become part of collar w/ strap that snaps. If you already own tons of various weight baselayers, this maybe right to keep winds off, but if you already own Marmot DriClime jacket/wind shirt this may be a redundant piece.