First, let me say this is a great cap idea. It does a great job at letting air flow. The problem is the sizing. I have it sized all the way down and it is still a little loose in the wind. I wear a medium in other OR hats, but this is swimmingly large. I'm looking at replacing the strap design with Velcro, hopefully that will allow me to adjust it to an appropriate size.
I spent months looking for a rain jacket and reading numerous reviews before buying the Aegis Jacket; which is sold out practically everyplace.
The jacket is very well designed and offers decent features: pit zips, adjustable hood, rain resistance.
I sized the jacket using the Marmot guide, which put me into a medium. I'm 5'8/5'9,150 lbs, 32/33 sleeve,37" chest, 31" waist, 15.5" neck. The jacket fits perfect in the sleeve, its JUST long enough (note that the velcro is very skimpy in terms of adjustments). The length is good. The neck is good. The body is horribly large, large enough that it will fit over my MH Exposure Parka, size small. The body chest size is much closer to 42". Even with multiple layers its too large.
As much as I like the design, I'm not keeping the jacket. The sizing is just too poor. Unless your built like a barrel, with short arms and a short torso, look elsewhere.