I'll throw in what I know...because I keep searching for the perfect Florida-heat helmet. I have had HJC, Joe Rocket Carbon, other brands I can't remember...trying to stay in the $225 and under category.
I keep coming back to Scorpion. Call me crazy, but I like them MORE than the Shoei's. Love the interior, love the looks.
I have an Exo 700 and several exo 400's. They use the same shield which is great - and they are the best no-fog shields I've come across so far. The difference between these two are the materials used to make the helmet, but other than that the same shape, specs, and liners. (Removable, and a $25 replacement!). The 700's are lighter and have better venting.
The newer models are the 750 and the 500, which have the internal sun-shield, and I don't care for those at all. In a wreck, they will cut your nose off, and they're just not dark enough.
Hope that helps!