TXi
After many years (20) and many helmets later, the TXi by Arctic Cat is by far my favorite. Our family uses 4 of them. And only 1 Cat sled.. LOL
My helmet priorities are no sheild fogging, and how warm is a helmet. This helmet is great at both, its warm (not drafty) and hardly every fogs. I have a heated sheild on it but seldom need to plug in because its got a great seal around your eyes to keep your breath away from the sheild.
I have tried the modular Doo helmets, and they do work but they are to fiddly, to many moving parts, to much to go wrong, and far far more expensive than the $180 price for a TXi. But besides that I would still use a TXi if the prices were reversed.