I purchased a Shark RSR2 helmet (their top of the line model) at the beginning of this riding season and wrote a review of it here.
The helmet comes with a breath box that, if it is in place, pretty much makes it impossible to fog up. Shark currently offers 5 sport helmets:
The S650, which is their bottom-of-the-line full face helmet. It’s not worth buying and is missing most of the features that set Shark helmets apart from the rest.
The next step up is the Shark RSF3, which has what has been described as a “neutral” head shape. It’ll fit everyone decently but won’t fit anyone especially well. It’s a good buy for the price but if you can afford to step up to something better, by all means do.
Next is the RSI, which has most of the features you would find in their top of the line helmet for a lower price, but is made specifically for “long oval” head shapes, like the Arai Profile.
Their highest end helmet is the RSR2 which is the most “round head” oriented helmet in their lineup. Its shape has been described as being nearly identical to the Shoei X-Eleven.
Finally there is the Evoline, a modular/convertible helmet that is unique among modular helmets because the chin bar relocates so that it can switch back and forth completely from an open face helmet to a full face helmet.
You won’t be disappointed with any Shark helmet you buy as long as it isnt the bottom of the line S650.