The MOST important factor is fit - on your head and in the car. Many years ago a poor fitting helmet was the primary cause of a dislocated jaw. The helmet fit tightly at my forehead, but not around the side of my face. In a crash the helmet whipped around, twisted, and caused a number of problems. I also had a concussion. Of course I probably would have been dead if I hadn't been wearing any helmet, so I'm not saying the helmet was bad. But a better fitting helmet might have caused fewer injuries. Around 2000 or 2001 I tried some helmets on in the car. Several pushed my head forward because of the combination of the design of my seat and the shape/size of the back of the helmet. Recently I tried on a Bell GTX, but it hit the front yoke of the HANS, so I couldn't use it.

An important point for some is weight. My previous helmet was a Bell Vortex because of the combination of fit and weight. I decided that even though it was expensive, the total yearly cost over about 5 years wasn't all that bad - and I was worth it! Because the Vortex is a '95, I had to get another. I tried on Bell first, then Simpson, Arai, Impact, and another I can't remember now (something with HJ in it I think - someone had them on sale at Topeka). In my case, the Arai fit far better than anything else, and was light. It was also expensive - but I'm still worth it. :P