Cow Hide vs Horse Hide
Horse hide is a hard rolled, more dense, tighter fiber leather. The horse hide has the advantage over cow hide if it gets wet from sweat, humidity or even an untimely rain storm by it's ability to resist stretching. For high sweat environments or very humid locations, the horse hide may be your preferred choice. The horse hide is a bit stiffer by nature and takes a slight bit longer to break in but is it these very features that provide the sweat/humidity performance level you may desire now or in the future.
The downside of the Horse Hide is that it is stiffer when new and takes a bit longer to break-in.
The horse hide does require an "up-charge" ($15.00) due to its availability and naturally higher cost. The horse hide is only available in its beautiful, natural, Russet Tan color due to its resistance to the dyeing process.
Because of the features described above, horse hide is generally considered one step in quality above cow hide.