100% agree that a correctly fitting helmet is the main aim and is worth paying for if that’s what it takes. When I tried on the Arai Profile I just knew it was the one for me despite the cost. Worth pointing out for the new folks that Arai makes helmets in different shell shapes so don’t give up on them if the first one you try on does not fit. I believe all others have the same basic shape and just change graphics and vents (but I could be wrong on this).
I’m going to disagree slightly with some of the advice above. While I have no doubt the exterior shells all have more or less the same protective ability, the interior fit can make a difference. Both my Scorpion EXO-400 and and Arai Profile are for 60cm oval type heads but the Scorpion has much thicker inside padding. Kind of like squeezing your head into a sponge. The Arai by contrast just fits, more like putting on a glove. This extra inside padding does not help in a crash and I believe is more dangerous as it allows your head to move around within the helmet.
But I *think* this is a small concern. I would not hesitate to recommend a Scorpion to a new rider if the $400 saved was spent on good boots, jacket etc. The top of the line helmet can come later.