Ryan T. wrote a review of Patagonia M10 Jacket - Men's on February 21, 2011
Have had my mango M10 for about a year now. I have used it quite a bit, mostly biking and xc skiing.
Let me say that I love this jacket. 3-layer waterproof, breathable protection in something like 10 oz. The material almost feels papery(think Patagonia Houdini but waterproof). The pit-zip/pockets is a terrific weight-saving element. It really has little mass so I can take it wherever and not care. Functionally I don't have a single complaint.
I have worn xs in Patagonia's Rain Shadow but I found the xs in the M10 just a little too "athletic" fitting. But I am also not concerned with seeing footholds and such. I also wanted the ability to wear a heavier fleece like an R2 with this particular shell. The xs would not have allowed that. Also of note, the arm length runs a little longer than some of Patagonia's other less "technical" shells. The hood has terrific adjustability, even working well with my larger biking helmet.
All in all, I would highly recommend this piece if you can handle the price. Spartan design at its peak! Everything you need, nothing you don't.