The EPF fan is running a copy of landers current rotors, imho not a very efficient design. But thats not the real issue with their fans, the rotor material is (see photo). Metal blades are illegal in AMA regulations which is why noone makes them for props or EDF (which is considered a shrouded prop).

As for the WM300 fan, biggest problem there is it takes 70 AMPS to get a kilo of thrust out of one, whereas any plastic 64mm fan will produce over a kilo easily on 40 amps. This is a huge issue when you look at the size of the airframes that use 64mm fans, most can carry a 2200 4s1p pack, some can just get away with 2500mah 4s1p. A 70 AMP load will need a 3300mah packminimum which most 64mm airframes wont carry, it will ruin the airframes dynamics.