I have no experience with Icon helmets, but I bought HJC helmets for my kids (son 12, daughter 10). My daughter needed the youth L/XL (CL-Y) and didn't fit in the adult XS, but my son wears the M in the HJC CL-16. My wife and I both have Shoei RF-1100's, so that's my basis of comparison. I'm in an XXL and she is a M. The youth is only DOT, but the CL-16 is also SNELL 2010.
The CL-16 has all the features on paper you'd look for as compared to the RF-1100, but at a 1/4 to 1/3 the price. Of course, there's a lot of fit/finish differences, but at around $100 ($130-$145 MSRP), the HJC is sweet. It has a good quick release visor, fully removable liner (but not the chin strap covers, as far as I know), weak to moderate ventilation, and comes with a clear pinlock and insert (great value). Of course, it doesn't come with a chin curtain, but I bought one and it fit and matched fine. I had to replace one of the quick release shield plates because it wouldn't lock open when the shield was off. It was a fairly cheap and very easy swap. I bought my son the gold mirrored shield for it and it looks good. He has the yellow Hellion pattern.
The shield detentes are not great, but work for the price. The Cl-16 doesn't have the internal sunshade, but web bike world usually gives them bad marks for added weight and if you ride in the rain, the rain gets in and drips down the sun shield on the inside of the helmet.
I'd look up any helmets you are considering on
webBikeWorld and check their review. I'm a huge fan of the Shoei RF-1100, but it's about 1.5 to 2x your price range, and most helmets will give the same protection, it's just comfort and price at this point. The new Bell line has gotten great reviews. That might be another manufacturer to check out.
Give us a review and some pics of whatever you end up buying!