MF2
Chipset: Ambarella A7
Highest Resolution: 1296P
GPS: Included
Opia 2
Chipset: Ambarella A12
Highest Resolution: 1440p with HDR
GPS: External and not included
Quick release bracket
The Opia 2 is the better choice featuring the better hardware and quick release bracket. It also seems like the MF2 has a weird mount with the power supply built into the mount from the pictures I glanced at where as the Opia 2 it is separate.
The Opia 2 can also use a CPL filter if you'd like. If your budget can swing it I would defiantly grab the Opia 2 over the MF2