I tried on about 10 helmets when I bought mine and none compared to the Xen by Giro...granted it was $169 at the LBS but I went and found it online much cheaper. My girlfreind wears a Specialized helmet and likes it a lot and it was 1/3 the price of mine so it all comes to fit.
With things like helmets...you try them on until you just know its the right helmet...price is second.