This is a very interesting system and I do not regret my puchase at all. But as a system itself it feels very incomplete. I would say if you plan to run this game you also need the core books for Dungeons and Dragons 5th Edition. It explains many of it's new rules well and they are fantastic editions. In particular it's Supply and Magical Mishap rules can only be described with a chef's kiss. But most of it's rules are so rules lite as to be non existant on it's own. In many ways it's like Original D&D. Where OD&D was a bunch of guidelines based off the game Chainmail, this is a bunch of guidlines based off 5e. But I feel as if this system needs an Advanced edition or the Basic/Expert treatment.
If you have the D&D 5e books you should definately get this! If you don't already have those books you may consider giving this a pass.