I have/had an AC-12, and I liked it except for one thing. When riding at speeds above 40mph, I'd get a big red mark on my forehead and start getting headaches. My head is more of an elliptical shape, and the inside of the helmet is round. It also lacks padding in the center of the forehead area.
Besides that, I loved it. Wasn't too noisy, actually takes abrasion well (though I will be throwing it out), and was very light.
03 919 (most of it anyway)