Just picked up an AGV Horizon. My previous helmets were both Arais, a Quantum and Profile. Size-wise my Arais are Large but I went with a Medium for the Horizon. I bought the Profile when I picked up the bike in '06 and I felt it was time for a new lid. The Horizon feels really snug but not uncomfortable, it should be fine when it breaks in.
The main things I've noticed with the Horizon so far:
- has more ventilation vs. Profile which = more noise
- chin takes some getting used to which makes it feel bigger
- the ISV (Inner Sun Visor) not 100% optically correct, minimal distortion but nothing distracting (really slight, some might not even notice)
- can't "crack" the visor like Arai for stop and go traffic, but has an anti-fog visor which seems to really work
- both weigh about the same
- main visor is easier to change than Arai
I wanted to get another Arai but found a price on the Horizon that I couldn't pass up.
Overall it seems like a great helmet, I have no complaints so far. Since I'm a commuter it's great that I don't have to carry 2 visors with me anymore.