+1 on the Rab Demand. I really like mine. It's sized "British", which is perfect for me--at 5'9" 140 I bought the medium and it's great--but slightly too tight for a winter puffy underneath. Definitely size up if you're on the cusp. And yes surprisingly I don't mind the lack of pit zips for Event. The Demand does have a deep chest zip that can function as a vent. Overall it's 3 ply bombproof and very light.

I wouldn't say eVENT doesn't require pit zips… I can easily overwhelm eVENT ability to move moisture. All I need to do is hike 3mph up a >15% grade and I will be swimming. It's all about trade-offs. If I manage my activity level, I can do ok with eVENT without pit zips, but pit zips are useful… just for me, not worth the extra complexity and weight. If the jacket wasn't used in town, I would have gone for the pullover.

The second best material I have used is Montbell's BreezeTech (my daughter stole my Montbell Peak Jackets which is why I eventually purchased a new jacket). I found that the Peak with pit zips open was as good as an eVENT jacket, but not as good with vents closed.

--Mark

http://andrewskurka.com/2012/breathability-its-importance-mechanisms-and-limitations/

Anna, I'm so glad you linked to that article. Surka is one of my favourite hikers who has such an extensive experience that anyone would be mistaken to question his advice. There is also a really good discussion going on about dew point in down bags in high humidity conditions (http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=54121&startat=80). Since we are being misled on what will actually keep us dry and warm, we need to educate about the nuances such as dew point, heat exchange, vapour transmission, and more. What I figure is that with a more breathable material as a rain shell I should be able to push water vapour out rather than equalizing humidity (100% outside in rain and fog/ 100% inside from perspiration and internal transmission of humid air). I don't remember much from chemistry courses but diffusion acts as concentrations differ across a porous membrane... but by adding something like heat to one side I am hoping the equilibrium can shift. I'm not a thermal engineer and not sure if raising the internal temperature would accomplish my goal... can anyone speak to this? So the more porous the easier it will be to adjust the equilibrium.