I own several helmets as we play in the dirt in the summer. I have the bombi bv2s mod and my newest is the klim helmet. I think they all have good an bad traits. The mod is the warmest helmet I have, however for me it is a problem as I sweat bad when working in the mtns. Fogging is not an issue with this helmet, but it gets heavy and I usually am taking it off every time we stop. With the klim I find I leave it on all day, unless we are stopping for a long break or lunch etc. It is lighter and keeps my head cooler. I think on super cold days the mod will be what I wear and on normal days the klim.
Anyway, if you go mod I would get the bombi helmet, it is pricey but works very well.
Anyway, if you go mod I would get the bombi helmet, it is pricey but works very well.