The first “differences” response was pretty generic. The ST-24 provided more “finger tip” camera control functionality than an ST-16, which made the -24 a much better camera controls device.
The 920 also provided for Team mode using either another ST-24 or ST-12, something not possible with a 920+ unless it is used with a CGO-3 in conjunction with the Typhoon H flight mode. Having team mode capability combined with camera and lens options made the original 920 a true aerial videographer tool.
The 920 also provided the option of using different cameras, which included the GB-603, CGO-4, GH-4, a7, and an 18 power zoom Yuneec camera. The 920+ is limited to the CGO-4 and CGO-3.
Propellers are the same for both. Quick change adapters came stock with the 920 Plus but became an option for the 920 when the Plus was released.
There have also been reports the original 920 provided more flight time than a 920+.
The 920 Plus is less stable in wind than the original 920.
IMHO, the 920 Plus is a significantly down graded version of the original 920.