Most everyone seems to like OTG cables but I really don't think using the Wifi connection between controller and phone is bad. Even without OTG I've gotten over a mile of distance with still decent video.
My only comment on Litchi and the Spark is the Spark seems to "crab" a lot when it's at all breezy. In other words it is moving towards 12 o'clock but points at 1 o'clock .
I didn't know that it didn't until after I tried it. When it wouldn't work (works great with DJI Go) I came here and found several threads talking about no Litchi with OTG.
