Bicycle helmets only protect you from bustin' your head wide open. They are not designed to protect against concussion and more expensive helmets are not better in terms of protection just 'cause they're more expensive. The cheap ones have to meet minimum requirements as do the expensive helmets. The difference comes into play with weight and venting. Less weight means less materials and/ or higher grades of plastics to offer the same protection. You may also find better chin straps etc. I have a Bontrager Lithos. It's the best helmet I've had yet.