Brand doesn't matter much. Neither, frankly, does price*. What is most important in protecting your noggin is fit. Find a decent race shop. Try a bunch of them on. Buy the one with a Snell SA2015 certification that fits the best.
*One could make an argument that more $$ buys less weight and potentially better ventilation. But, again, those features aren't of much value if the helmet either flops around or gives you headaches from pressure points.