Wow Sparco, Arai and Simpson helmets...you guys must be rolling in the dough? LOL!
To me helmet selection just really depends on what type of racing/risks you are doing. I'm just auto-X here in hawaii on a small stadium parking lot so I use my Icon Motorcycle Domain 2 Helmet.
Since it gets hot at our site a lot of other racers use the motorcross helmet which are lighter and vent a little better.
If we had a real track I would probably break down and run with the Simpson Outlaw bandit in matte black and use with my Harley Night Rod Special too.