This is a fine kit, but it's a stretch to advertise it as open. This kit is based on HoverflyOPEN. In Hoverfly's words: "The HoverflyOPEN flight controller system is based on our core Sensor Data Fusion technology called HoverCore." "We can't tell you exactly what HoverCore operates or what types of digital filtering it uses. If you want to write the code yourself or use an open source solution...great."
I won't mention specific competitors here, but for $180 less than this kit, you could get a drone kit of comparable quality that comes with GPS and autopilot (as in fly-by-maps.google.com). These drones are truly open and have an active community.