I picked up this jacket at the end of winter and have been using it on a series of trips in the Cascades including the Common Wealth Basin, Mt. Baker and Mt. Rainier. The venting is excellent from the side zips to the front hand warmer pockets. As with any hard shell you do need to manage the vents to avoid internal dampness if you are working hard and sweating but I found this jacket to be exceptional in comparison to other jackets of equal weight and water proofness and durability. The side vent zippers work both from the arm pit down as well as the waist hem upward providing an excellent choice for venting depending on the conditions. I have worn the jacket in high winds, snow and a down pour and was able to choose the right amount of venting given the conditions.

While not an ultralight jacket it is light weight for the quality and durability of the material.

I have read reviews about the slim/tight fit in the underarm area but I found it to be a perfect fit for me. I found the slim fit to work great with a chest harness and during vertical ice climbing. The fit did not hinder my movement and was a benfit by not bagging up under the harness or pack straps and made it easy to get to the side vents. As with any jacket it would be wise to try it on and see if the fit works for you as well.

I used the Maximus pro-shell for an 8 day winter mountaineering trip in the Central Cascades. This jacket is as advertised and will hold up in storm conditions.

Got this jacket after returning my mentor for warranty issues(zipper). As always, OR takes care of it with no problem. This jacket is heavy duty without the weight-just a few more ounces than the mentor and still packs down to a little bigger than a nalgene(size M). This jacket is almost perfect except for one thing: The torso-flo zips don't even go up to the pit area. I can't believe they didn't think this through more. The only thing I can guess is that you can reach the zipper on the side you want with that hand as opposed to having to use the opposite hand. The Mentor jacket is absolutely perfect in design as its torso-flo zips go all the way past the pits to the biceps-perfect for dumping heat quickly. If OR can take care of this issue, this jacket would be one of the most durable and perfect jacket there is out there. My size: 6'1", 173lbs, 38"chest, 32" waist and 19.5" torso. Medium is good fit for me

I have been using the Mentor jacket for the last couple of years and been very happy with it but it tended to bunch up above my harness making it hard to see my rack and draws. This new maximus is a much better fit for me, I can climb and still see the gear on my harness which is a great improvement