Weathershedding
Patagonia’s H2No fabric is bomber stuff. The 3-layer membrane construction locked out heavy rain and melt-on-impact snow for hours. The generous hood easily fit over a helmet and cinched down for hunkering when it got really nasty. All the zippers are watertight. 

Breathability
Testers were very impressed with the breathability of the M10, even though it doesn’t have pit zips. One tester, who usually runs hot, was shocked that he could keep it on even steaming up a hill. 

Function
One tester found a harness blocked the two hand pockets and he found the hood’s brim lacking. It was floppy and tended to stick to his forehead. This is one of the few places where we feel Patagonia cut too much. For instance, an easy to grab single pull tab adjusts the hood handily. The cuffs feature tons of adjustment room without being overly bulky: we could cinch them snug or layer them over top of a pair of gloves. 

Durability
The M10 stood up to some thrashing climbs and ugly bushwhacks with little injury. It’s a light jacket, so it won’t be as tough as some heavier weight options, but we feel confident taking it for jungle warfare and it’s backed by Patagonia’s excellent warranty.

Packability
To shave bulk and ounces the designers at Patagonia used ultrasonic welding to join fabric, rather than stitches. Then they used the smallest seam tape they could. The result is an 9 ounce jacket that stuffs in its chest pocket. Impressive.