It adds horses that you can ride! Truly a wonderful reward for finding and taming a horse. It makes exploration and transportation so much better. It really opens up the map, especially if you don't want to go the teleportation route.
Make sure you use horse shoes though. Horse shoes make the horses go faster! If you don't know that, you'll be stuck with a slow horse.
Also, I found that the horses were still a bit slow. If you are the same way, I recommend upping the "speed" rating of the horseshoes by 1.5 times, so (steel,mese,diamond) = (7,9,10) becomes (10.5,13.5,15)
One of the few if not only existing author that takes their mods seriously to ensure critical bugs are fixed promptly. If your a serious server admin like me, you can't go wrong with their mods' collection and the fact that prompt support is normally provided to boot. :)