Three LEDs with one normal reflector would result in a bad beam pattern. with a specially made reflector, you could get a good pattern but that would cost more.
The WF-500 has many problems with heat, so unless those problems are fixed, I would avoid it and get the MX power.
I see that one Solarforce looks very similar to the MX Power. but it says that is is 700 lumens. Is this number been verified by someone. It seem a little high.