I have had this jacket for about a year now. I have used it in many environments and activities. Like all Arc’teryx jackets, this one is beautifully made and the fit is terrific. The cut is trim and athletic. I am 6’0”, 185lbs with a medium build and the large fits perfectly. In regards to layering, there is enough room for my Patagonia R2 underneath the jacket, but not much else. For more layering options, you may want to consider the next size up.
Please note that this jacket is intended for active outdoor enthusiasts. It is made with a PTFE shell (Gore-Tex) on the shoulders, arms and on the lower portion of the jacket and a softshell fabric called Tweave Durastretch used throughout the center of the torso front and back. The PTFE is obviously waterproof and the Tweave is coated with DWR for a fairly water resistant finish. The jacket has no problem with snow and light rain. It can stand up to medium to heavy rain for short durations. The Tweave provides good stretch characteristics and is highly breathable which also means it is less wind resistant. If you are sitting idle in colder windy conditions, you will lose heat due to the highly breathable nature of this jacket. Since it has no insulation (shell only) is does not generate warmth for the user. However, due to its highly breathable nature, it is great for all high output activities. If you generate heat while active, this shell breaths and releases the heat to maintain a comfortable body temp. I can assure you that no direct venting, core vents or pit zips, are required. The jacket appears to be very durable. I love this jacket but I would not recommend it for around town use. In that application, the comfort zone is somewhat limited.