i've got a KBC Racer-1 and love it...
here's my reasoning:
-believe it or not, i tried on an Arai and a Shoei before my KBC and i actually felt the KBC fit my head the best. The padding just felt alot better. I've since tried on a Suomy and that will be my next helmet.
-i love the way it fits, i love that its quite light. I love the styling, i LOVE the price (145 on motorcycle-closeouts).
-Yes, its loud, but there isnt a helmet out there thats "quiet". However, i ride a motorcycle. I am not really trying to quiet things down, i operate loud machinery and listen to loud music so a quiet helmet is not really a huge concern. Another reason people say the KBC is a little louder than normal is because its SUPERBLY vented. It never fogs up, and its always ventilated in the hottest conditions.
-my only gripe is that there is no changeable visors for the helmet. I dont do alot of night riding so i wish there was some kind of mirror or tinted visors to keep me from wearing shades.
the biggest factor: i feel safe in this helmet. God forbid i had to test it out, i'd feel confident that this helmet will save my life. And at the end of the day, thats the only thing i really care about