Hi @LeoSeg,
Normally I try not to recommend one sensor over another and instead just recommend reading over the various optical flow options listed on the wiki.
… but one important advantage that the HereFlow has is that it has an onboard gyro so that it can provide the sensor’s rotations directly instead of AP needing to use the gyro values from the autopilot (which are slightly different because they are mounted in different locations on the frame).
I have also heard good things about the ArkFlow sensor but I have not tested it myself nor do I know if it has an onboard gyroscope.
EDIT: I think ArkFlow also has an onboard gyro because it uses the same AP driver as the HereFlow.