This is a very light helmet. For me personally, that was not the main motivation for buying it, rather I got it on a great sale and liked the color and overall design. It does lack some adjustability because of the minimal weight, the most noticeable for me being the lack of fore and aft adjustment of the chinstrap and that it runs slightly large. My head measurement falls right in the middle of the fit range (59cm, L says it fits 56-61cm) and it barely gets tight enough for me. With a cycling cap or headband, no problem but if you prefer to ride with nothing under your helmet and are on the smaller end of the size range, you may consider sizing down. All in all a great lid. Holds my glasses well when off my face and interfaces with them well when on (Oakley Sutro/Sutro Light). Vents well and looks good. I haven't crashed (knock on wood) so can't speak to protection, but POC is a reputable brand so I am not concerned there.
I really like the idea of a light that is custom-made to fit my helmet, and it does indeed fit well, with no noticeable added weight or bulk. It is bright -- I worry that it might be too bright and thus annoying to drivers, but no one has honked at, yelled at, or thrown anything at me yet. Wish it had more options than steady & flash, and the charge does not last as long as the blinky I had been using previously. The biggest problem, and it is a big one, is that the light snaps on very loosely, and it is very easy to knock it off if you are adjusting the helmet's roc loc wheel. I've had it fall off a number of times--though always from me bumping it with my hand, never just from bumpy riding. I may zip-tie or even glue it if it falls off again.
Finding the helmet lightweight and well-ventilated, though I haven't had the chance to wear it in hot weather yet. The fit is a bit more circular, less oval, than my previous Giro helmets, which is something of a bummer, as it leaves a little wiggle room around the temples that can't be adjusted snug. Still, it does not seem to slide around or be less secure because of it. I love the reflective finish -- truly eye-catching to drivers when riding in the dark. Also like the fact that a custom-fit rear blinky light is available for this helmet -- though that product has its own issues (Giro Roc Loc 5 LED Rear Helmet Light).