The best thing about this helmet is how light it is--at just 205 gm for the medium and comfortable to wear. I ride about 100 miles a week. The screw to tighten the inner cuff that customizes the fit on your head is small and sits above the neck and is difficult to access when riding. I had another road helmet where the screw was much easier to access on the top I have to fix it on the POC every time I ride and sometimes mid-ride. I also wish this strap fit better but it constantly slips loose and is made of a flimsy material that twists easily. I have a small head but this helmet makes it look big--it has a boxy profile--however it has excellent vents and the color is good and bright for visibility. I wound up ordering another brand for my warm season helmet, which is smaller, has a (preferred) MIPS interior and a slimmer profile that I will use for the warm 6 mos of the year-- and reserve the POC for winter training.
This POC (Ventral Air) successfully checks the same boxes that had me raving about it's "lesser" sibling -- the (Octal). It's light, ventilation is good, and it's so damn comfortable. The only think keeping it from earning five stars across the board is the price, which is a bit steep, especially considering the Octal, in my opinion, is easily as good for $50 less.
My bottom line, having tried Giro, Bell, Kask, Bontrager helmets, I'd rate both of my POCs better than the whole lot of them.
I made the switch from Giro to POC a few months ago and couldn't be happier. The white one is great for early morning rides when the sun is still rising it is much more visible. The air flow is great and the helmet is light I never think about it on my head. I got this on sale and would not have paid $280 for it as I don't find it much different than my Octal which was like $150. I got a M and could have probably gotten a S but it fits fine!
The Ventral Spin fits exactly like my Ventral Air Spin, and weighs just 19g more (298g vs 279g). The Medium helmet fits nicely on my 57cm circumference head, with ample room for a cap underneath. I've only worn the Ventral Spin on cold and mild days, so I can't say how it performs in hot weather. However, it does seem "quieter" on windy days than other helmets I own. Fluorescent orange is great for safety, especially during low-light fall and winter days.
The helmet's only downsides pertain to sunglasses: 1) the "sunglass garage" flat out doesn't work, and 2) the arms of my POC Do Half Blades bump the helmet's back edges behind my ears if I don't position the arms just right. I've read this is a problem with other sunglasses as well, but don't have other sun glasses to test for comparison.