YAPU - Yet Another Pokémon Unity - is an attempt to create a Pokémon framework in a more modern engine, Unity in this case. Its main focus is to take advantage of Unity's powerful editor tools to allow developers to create a complete game without having to write a single line of code and without having to leave the Unity engine. On top of that, Unity allows to deploy the games on multiple platforms, without doing any of the juggling needed to play RPG Maker XP games outside of Windows.
That said, YAPU does not attempt to replace Essentials, but rather provide an alternative for those that feel more comfortable working with Unity than with RPG Maker XP.
While YAPU aims to be simple to use, it uses several Unity features that may not seem intuitive to newcomers, so it is recommended that you at least go through some Unity tutorials and familiarize yourself with the engine before trying out YAPU.
For more information about YAPU, check out the documentation.
That said, YAPU does not attempt to replace Essentials, but rather provide an alternative for those that feel more comfortable working with Unity than with RPG Maker XP.
While YAPU aims to be simple to use, it uses several Unity features that may not seem intuitive to newcomers, so it is recommended that you at least go through some Unity tutorials and familiarize yourself with the engine before trying out YAPU.
For more information about YAPU, check out the documentation.