Aether Conquest is built around a custom gamemode with custom-coded features, so it does not feel like a plain box server. The closest comparison is a box server, but this one goes a lot further with extra content and systems built in.
You can expect a level system, custom crafting, boss spawns, and a PvP setup that changes things up instead of staying static. There is also economy style progression mixed in, which fits the prison side of the server while still giving PvE and PvP players plenty to do.
The server is planned to keep getting updated with more exclusive features over time, so it sounds like a project that is meant to grow instead of staying the same. If you like custom mechanics, progression, and fighting both players and bosses, Aether Conquest should be a solid fit.