Recently used this while snowtubing during a cold morning, and so many people came and asked where I got it.

Pros:
1. Warm mask for protecting your nose and mouth
2. Unlike a scarf pulled over the nose, it does not fog up my glasses
3. Very easy to get on and off (unlike a neck gaiter tube) and the twin velcro straps hold on very securely
4. Does not mess up your hair like a full mask

Cons:
1. Smell can take some getting used to
2. Velcro snags onto everything causing intense pilling (including parts of the mask itself); ruined 2 of my gloves. Wish there was an alternate strap mechanism
3. Not as warm for the neck as a scarf; good to keep a scarf as well
4. Wish it went higher in the back to protect ears as well. Ears are only partially covered and you need to use something else.
5. Expensive

I usually wear it with a 180s ear warmer on moderately cold days, or with a beanie on bitterly cold days.