I bought these for snowshoeing and they work exactly like they should.  I was skeptical of the attached/non-replaceable underfoot straps but they seemed quite durable.  Time will tell.  I can only imagine that using them for hiking on rocks/rough ground would potentially wear the strap out much quicker than snowshoeing would.  I was also concerned about the strap buckles rubbing against the snowshoe straps but they are quite unobtrusive.  The design of these gaiters makes them easy to get in and out of and they seal nicely around the footwear.  The upper straps/buckles hold shut securely and are also unobtrusive.  You essentially forget that you have them on - which is the way it should be.  A satisfying purchase. In regards to size - I had purchased a medium pair for my wife and a large pair for me based upon the manufacturer's size chart which is based solely on shoe size.  It turns out that the mediums fit me (size 11 shoe) and the larges fit my wife (size 9 shoe) due to her 16" calves.  They mediums will not fit someone with 16" calves.  They should really size them by calf size and not just shoe size.