I have both a snocross style and full face (both HJC) and I used to never wear the snocross one below about 15 deg F due to the issues you noted, although not so much my nose but the area around my cheeks and under my eyes. Since then, however, I got a different breath deflector and did some work making sure all of my skin was covered around my goggles by pulling the sides of my breath deflector way up to the sides and now I'm able to ride at beow zero temps comfortably. The full face is still warmer but I like the leight weight & great visibility of the snocross style. I have the stock low Apex windshield so wind protection is zero - a higher windshield would certainly help. If you only could own one helmet, however, I'd opt for a full face to be safe so you're not left freezing if you want to ride at 30 below. If you can swing two then grab a snocross for the nicer days. Riding in the UP of MI, I find I wear my snocross about 75% of the time, the other 25% I opt for the full face.