One of the reasons Arai, Shoei and Suomy are more expensive is because they spend some of the money you pay for research, development and design. I support this completely.
Indeed, they use higher quality materials, take exterior shell aerodynamics, air through-flow, durability, shock absorption (among other aspects) into consideration in their construction and manufacture, and in many cases, will have better warranty and customer support.
I own five helmets and have just ordered two more.
Two (gorgeous) Icons (my 'poser' helmets), two Arai, and (after the new ones arrive) three Shoei. When I go shredding in the canyons, it's always, ALWAYS, the Shoei. I think you can see where I'm headed with my personal assessment/endorsement.
Remember this, always...you only need your helmet to work for you, once.
Ride safe, ya'llz.