PocketHorses is a plugin that allows you to turn any mob that you can put a saddle on into an item to be stored in an inventory. This plugin like many of my others was made and is updated for the server Envirocraft. The reason it was created was to replace an old plugin called zHorse, it was intended to improve upon zHorse in serveral ways.
Update timing / consistancy
The plugin that PocketHorses was built to replace (zHorse) is a free plugin has no strict update policys (which it shouldn't) however this did prove to cause some issues when updating but keeping the same world, as people would leave their horses everywhere but after an update no longer be able to locate them as they have forgoten where they left them.
PocketHorses fixes this by being a relativly small plugin, and being controlled by me, meaning that it can be updated on my schedule and to my standards.
Performance
In order to understand where these performace gains were made you need to first know the difference between zHorse and PocketHorses. zHorse does not turn horses into items, rather it saves their UUID in a database and allows the owner to teleport the horse to them at any time. In contrast to PocketHorses turing horses into items that a player can carry on them, or in an enderchest for example. This aproach completly removes the largest performace hit that zHorse has wich is fetching a horse from an unloaded chunk, which around MC 1.13 when PocketHorses was first though of was a huge problem, though admittadly nowadays is probably less of an issue.
Ease of use
Usage of anything is subjective, but I would be remise if I didn't mention the fact that I am simply not a huge fan of having to use commands to do things as a player in a semi-vanilla enviroment. It just takes me out of the whole experince. That is why instead of exclusivly using commands to manage your horses, PocketHorses uses Crouch-Clicking to pick up a horse and a simple right click to place them back down. Could this have all been a command? Yes, but that would be a lot less fun.