There is a lot of interest on the new Sony RX10 IV and new Sony FDR-AX700, HXR-NX80 and PXW-Z90V Palm 4k Cam-Corders. We have found a couple of new sample videos showing these cameras in action with HFR high frame rate modes. We estimate all four cameras to have comparable image quality in HFR mode but depending on the price a better overall codec with more detail retention.
However the best value out of all of them could be the AX700 which costs about the same as the RX10 IV but in a more professional body with lots of control that the SLR form factor lacks. Also for a paid job you may be inclined to go with the more professional looking body to avoid judgmental stares.