I didn’t even know about the F9 gps or the better vibration resistance. Both will be appreciated. I found some good information about the F9: New uBlox F9 GPS test & quick comparison to M8 series
I wonder how well the F9 rejects attempts to bring the copter down by using gps interruption devices. I saw that the M8n series of gps’s has some countermeasures built in, and thinking the F9 probably does too. Either way, I’ll be glad to have both.