These work wonderfully in all but the very warmest conditions. The eVENT fabric is very breathable. (This was my first encounter with eVENT.)
My gaiters lasted about half a year. Tenacious tape stuck to the inside of the gaiter dealt well with the many tears caused by sharp sticks, etc. Tenacious tape didn't really stick well to the outside of the gaiter. Eventually the material became delaminated (and ultimately shredded) around the outside of the instep area. I tried repairing this area with super glue and, later, seam sealer. (Perhaps not ideal but it's what I had on hand at the time.) Neither were much help. It would be great if MLD came out with a slightly heavier gaiter with reinforcement in these key areas (similar to the Integral Designs gaiters, which I've only seen pictures of).
The simple design (which I like) means they are a little inconvenient to take on and off. However even in mildly warm weather the wonderful breathability of eVENT meant I had little motivation to remove them. They would have lasted longer had they not been so comfortable and unobtrusive.