I'll answer my own question! I called Marmot Warranty/repair dept., not their customer service reps... as they don't have this info. These are actual garment measurements..... Large followed by XL.Chest 51"/54". Sleeves ....37.5/38.5 Neck 23.5/24.5 Center-back length 29"/30"The jacket has 4 oz sq/yd Primaloft in the body, 3 oz sq/yd in the sleeves and 1.8oz sq/yd in the hood.I would call this the "Medium" warmth category for winter jackets. Having a multitude of Primaloft Jackets....Marmot and EMS.... the 4 oz weight PL in the body gives it noticeably more warmth than 3 oz alone. Having a bunch of Primaloft jackets..... this is not for severe cold... like -10 or anything....... but depending on the users activity level, metabolism and all.... should be OK for anywhere from above zero to 40 plus degrees. I find Primaloft jackets to have a wider temp range than down..... making good for 3 seasons here in the Midwest. For severe cold I layer different Primaloft jackets ..... warmer than any down parka! I've got a Marmot Belay Parka that has 7 oz PL in the body... and combined with a lighter PL layer.... it's a furnace. Wearing a PL vest over/under the Ellsworth will make for a very warm jacket.

I've not tried this one in particular, but being Gore Tex brand, it is "guaranteed" or your money back. http://www.gore-tex.com/remote/Satellite/content/care-center/our-satisfaction-guaranteeThat said, biking in a jacket like this will almost surely make you sweat unless it's at a very leisurely pace. Add rain and you're gonna get wet from somewhere, either inside or out. Will it leak or wet out? Maybe.... the only way to know is try it. Breathable? That's a gray area of all waterproof/breathables. Every person is different, so every person will tell you something different. Yes, it breathes, but to what extent depends entirely on the individual and how they function.Personally, I would never cycle in a WB jacket because I find even a uncoated shell lacks real breathability, so how would a WB one be better? It wouldn't. The only shell I do use is a Pearl Izumi Vagabond, with zip-off sleeves and a caped vent in the back. Ventilation is the key. Any jacket for cycling needs a caped back and some sort of venting, either pit zips or large chest pockets. If they made such a jacket in WB fabric, you'd likely have your best chance to stay drier from both inside and out.

http://www.kavu.com/sizingchartimage.jpg