I've worn AGV helmets for years. Of course since Valentino Rossi wears an AGV, that must make me every bit as good a rider as he is!
There was a small interlude when I replaced a crashed AGV with an Arai. With all the hoopla about Arai, I found that it was a very nice helmet - and I liked the AGV better.
The fit and finish of the AGV X-Vent helmet (a newer model is now available) is every bit as good as the vaunted Arai.
AGV advertises that their face shields are anti-fog and some are anti-scratch. I can tell you, with expereience, that the anti-fog treatment on their shields works! I've been riding all Winter in the Denver area without any fogging problem.
I have crashed in an AGV Q3, the progenitor of the X-Vent. According to my riding buddies, my head slapped the ground hard! I suffered no injury, pain or headache.
Please note: the 'race' versions of the AGV line fit very small. An XL Arai Quantum f is just a touch too large for me. The XXL AGV X-Vent is very snug. The street version of the AGV line fit more like the Shoei and Arai equivalents.
My next helmet will be another AGV.
Ron