Litchi does work with Spark and the RC using GearVR with head tracking but not with OTG. Wireless was much nicer though and I haven't had any disconnects yet.
that's why I was asking because the OTG disables a lot of functions and telemetry in third-party apps, Litchi for example. All functions and telemetry work using wifi, however (Litchi).
I use the prop guards frequently though not all the time. I think they look kind of cool, however, they did save a flight when I got into a Douglas-fir branch.
Having just completed some test on the Quick Shots my self I'd say the weakest is the Circle mode. Circle bounces around quite a bit, however, the distance was pretty close (12meters)