I haven't been out to test in the mountains yet, but I have had this piece for a week and it's solid. It keeps me warm hiking around campus all day long. I live in MN, and yesterday the weather dropped to -20F (-37F with wind chill) and I had my R1 Flash Pullover, Marmot Afterburner, and the Winter Guide on. I was warm all day long going to and from class. I haven't had any snow or rain to test it in yet, and I will report again after more rigorous testing. I am 6'0"/165 lbs, and the Medium fits very well, room to layer but not too bulky. It seems to be constructed well; the zipper goes off to the side a bit when zipped all the way up (more comfortable) and it zips very high to cover the face (very handy). Also, the hood is great to cover up your head, fits snugly so you can actually see when you turn your head. The only thing that I am not crazy about is the way Patagonia uses their pockets to double as vents, rather than having pitzips. Honestly, this jacket is heavy enough that two zippers wouldn't weigh it down anymore, and it means that you can't really use the pockets for your hands when you wear casually. Also, it has a tendency to get snow/rain/wind inside rather than just air to cool you off. Otherwise it would be a five-star piece I think, though I am judicious with my five-star ratings!

A great piece for COLD weather. Used this jacket for ice climbing in CO and got overheated. I think this piece would do better on the east coast where the winters are frigid. Cut is a little roomy for a technical jacket but at least you can fit another layer under it when the mercury drops. Nice and breathable.

Climbed Ben Nevis in winter in it. Wind/waterproofing is great. Pockets/vents are pretty crap at both jobs. Adjusting hood on the go with frozen hands is tough too, cuff velcro doesn't work when frozen. Keeps ya pretty warm and dry though.

I found this jacket at the Freeport, ME, Patagooch outlet, so make sure to look for sales.

Major pro: Nice length for a Patagonia jacket. The sleeves are nice and long, and so is the body of the jacket, so you can stretch out without exposing any under-layers. I'm 5'10" 155lbs and I bought a small. Fits me great, nice and snug, though I like my clothing snug.

The brushed fleece lining is fantastic and cozy.

Only con is the HUGE price jump from their Guide jacket (without the hood). An extra $125 just for that feature.

Everything else has been said.

Great jacket for winter activities- its windproof, great mobility, breathes well, has great pockets, and the lining is very comfortable. My only complaint is that this fall I was caught in a couple of cold downpours, and the jacket did very little to shed water after a minute or two. My shoulders and chest were soaked!

I have yet to take it out on the mountain, but for the week that I have had it just around town I have been impressed. I live in MN, yesterday temps got down to -18 (-37 with wind chill!) and I had my Patagonia R1 Flash Pullover, Marmot Afterburner fleece and the Winter Guide on. I have to say, just hiking around campus and waiting for the bus, I was comfortable. I'm a big fan of the hood--not enough softshells have them in my opinion--and it came in handy yesterday! Solid construction as usual with Patagonia, I am 6'0"/165 lbs and a Medium fits great, plenty of room for layering but still an athletic fit with only a light layer underneath. I have the blue color, though I wish I had gotten the red; service on this site was exemplary as usual. I don't get my gear anywhere else anymore.