The Good:
I did a lot of careful research to determine the best head covering for a windy sub-zero day in New Jersey, and this thing won.  My criteria were that it had to cover as much of my head as possible, stop wind enough that my nose didn't get cold, keep my peripheral vision clear for driving, and modularity would be a plus.  This did all of those things and more.  With the draw string tightened, it turns with your head so you can look out the side mirrors and even at the blind spots without any vision obstruction.  Perfect for driving around without a heater in your car.  I endured a blizzard with 40mph winds, in which the snow was moving horizontally, and I was just find with this balaclava under a nylon hood (think windbreaker).  I've had wool caps over it, used it to keep my hair flat while drying, and used it as a scarf.  It performs like a champ under all circumstances.  It also works to keep you warm when wet.  One bonus none of these other reviews are going to mention is that you can make a puffy area in front of your nose/mouth and your exhales will create a moist zone that makes inhaling a lot healthier and easier.  This air warming and moisturizing is one of the main functions of any scarf, but this works a lot better than the scarfs I've used because you just pull it over your head and you're set, as well as how I didn't notice it freezing to my face.  The drawback is that one of the three of them I ordered had the drawstring in a different configuration so that it was under my nose.  Maybe I ordered the wrong thing from Rothco, but it got annoying and made my nose cold.  The one in the picture for this product is the good one that has the drawstring at the back, keeping it out of my face.  It also acts as a decent (better than nothing) mask to keep people from catching your flu and from catching their flu, since the moist air inside makes flu stick to it.  Flu spreads best in dry air, and this makes your mouth surrounded by moist air.  If you've ever seen what smoke does in the fog, that's because particulate matter doesn't stay airborne very long in high humidity environments.

The Bad:
Every time I walk from my ice cold car to a store, I have to tear this off before I get to the door.  If I start opening the front door of a Dunkin' Donuts without taking it off, I get about 4 people staring at me, one of which looks like he's about to pull a gun and make my day for trying to rob his store.  This looks SO much like a Counterstrike Terrorist costume that I had some lady in a diner almost choke on her toast cause I didn't get it off fast enough on the way in a diner, and I wasn't even in the diner when it left my head.  My state is full of places with large front windows, and people will start getting ready to press the alarm button before you get within 90 feet of the door with this thing on.

Conclusion:
That said, I'll keep buying these until I'm sure I will never be without one, because it's that good at what it does, for a very low price.  This slaughters $50 hats for the same purpose, when paired with something another head layer like a hood, and if you're in a car where there is no wind, but there is also no heat, this will be perfect down to about 20F, after which you can toss a wool cap over the top of it and then it's good down to below 0F.