Which Rx Protocol for my Flight Controller

Betaflight
For Betaflight controllers, use either SBus on older firmware revisions, or SRXL-2 on revisions that support it. 

If using SRXL-2 please use Ghost firmware v1.0.0.6 or later to workaround an issue which can cause failsafes after just a few lost packets. 

Kiss
For KISS flight controllers, which don't yet support SRXL-2, SBus is the only available option. 
Please feel free to contact Kiss and ask them when they are going to implement the GHST protocol in their awesome flight controllers. 

Flight One
For Flight One controllers, please use SRXL-2 if supported, SBus if not.