Firstly, I am a huge Janji fan and have turned many onto the brand. I have the Rainrunner Pack Jacket and Thermal Zephyr Runner Jacket, both in XS. Love both. This one missed the mark for me.
I was hoping the fit of this vest would be similar to the other jackets, but the shoulders are cut a little narrower. I'm not broad-shouldered, by any means, but the top seam doesn't cover most of the shoulder as pictured on the product page. It stops at the pointiest part of my shoulder and the downward cut + elastic cinching creates puffiness at my traps. The body of the vest is already quite roomy, so going up in size isn't an option. Laid flat, it's an inch wider than the Thermal Zephyr Runner.
I had also hoped the insulation pattern would be more similar to the Thermal Zephyr Runner - gloriously breathable under the arms and middle back - but the difference in thickness across the various panels of this vest feels negligible. If cozy is what you're looking for, this might fit the bill, but I'd expect to pay less for a vest with this level of tech.
One last note for the suggestion box: the chest snap should be standard on all Janji outerwear!