This is a discussion topic for the Ore project, LuckPerms. View the full project on Ore for downloads and more information.
LuckPerms 
An advanced permissions implementation for Bukkit/Spigot, BungeeCord and Sponge.
Links
Description
Why LuckPerms? There are a whole variety of other permissions plugins out there. I’ve used a variety of other solutions over time, and found that they all lacked features in some way. LuckPerms is an advanced permissions implementation aiming to be a flexible, performant and reliable alternative to other permission systems, providing all the features you could ever possibly need in a permissions plugin, along with an extensive and well documented API for developers.
LuckPerms vs Other Plugins
Features checked on 8th Oct 2016. If you find any inaccuracies, please do let me know. I tried to be as fair as possible, and copy all major features from the respective plugin pages.
Installation and Usage
You can find a complete list of commands and detailed installation instructions on the GitHub Wiki page.