Let me note at the outset…these are for road shoes only and are not compatible with gravel or mountain cleats (SPD, eggbeater or otherwise). For off-road and gravel use, I still recommend the Shimano MW-81 shoes (which, three years in, are still functioning perfectly) or, for extreme cold weather, Wolvhammers. But with road shoes, the use of overshoes can be a great season-extender.
You can see them in use, on Mr. Pink, here:
The overshoes are not neoprene. Neoprene is very warm and waterproof, but is not breathable. These overshoes are made from a 3 layer laminate fabric that is waterproof and breathable. They have taped seams and a covered zipper that adds to the weatherproofness. The sole is made from a kevlar-impregnated fabric that is supposed to be very durable. The zipper also has a nice guard on it that keeps it from cutting into your leg when zipped up.
Coverage on the overshoes is great. They cover the entire shoe, and come up above the ankle to integrate nicely with a set of winter tights.
From my riding with them thus far, I can confirm that they are waterproof and breathable. My road shoes have a lot of vents in them, and the overshoes do a great job of covering those openings up. They also have some nice reflective features, which is appreciated when riding at night.
I’m surprised by how warm these overshoes are, when paired with a set of wool socks. They greatly extend the season for road shoes.
The downside to these, or any overshoes is that they do not do anything for the cleat. That’s the downfall of road shoes. In cold weather, the cleat acts like a giant ice-cube under the ball of your foot, and pulls all of the heat from your foot. If the temps are low 20s or below, I can only wear these for rides of 90 minutes or less, or the foot pain from a cold cleat becomes too intense. Even then, the end of the ride gets quite uncomfortable. Perhaps using a winter insole or a chemical heater would improve conditions, but frankly, when it gets that cold, I’m usually not on a road bike, outside, for longer than 90 minutes anyhow. At that point, I’m usually riding fat, gravel or mountain.
From an economy perspective, these don’t make sense for everyone. If you’ve got a set of winter shoes like the MW-81s, I’d recommend picking up a spare set of pedals and just suffer along with some mountain cleats on your road bike for winter riding. (I’ll throw some Crank Brothers Candys on my road bike for extreme cold). But if you’re just looking to extend your road riding into temps below the mid 40s, when you need some sort of shoe cover, the Overshoes are pretty fantastic.