I came across this thread, in my search for an new OSD.
Nice video, all explained well. (nice location btw).
After watching your video, and reading the manual, one question came to my mind. You are talking about 4 flightmodes (manual, alltitude, gyro, and return home). In the manual they are talking about only 3 modes.
I like this OSD a lot, i found it during my search for a Skylark OSD, with RTH. This looks more solid to me.