From my personal testing, the Wiedamark seems to have a much wider beam angle, where the AMDJ LED Pro is more focused. The AMDJ, therefore, SEEEEEMS brighter but I think that it's only b/c all of its light is more focused in a smaller area than the Wiedamark. Also of note, the colors in general (especially purple and blue) of the AMDJ seem richer to me.
I've compared both of these to an Elation Design 36, and I must say the Design 36 ABSOLUTELY KILLS both of them. This should be expected though for the price difference (approx. 3:1) right? At first I was scared of the price, but after comparing, I realized one Design 36 will easily replace 4 AMDJ LED Pros. The Design 36 is a little bit bigger than a PAR 38 and has the output equivalent to about a 700W tungsten bulb. I have decided to go with 6-8 of the Design 36's for front lighting. For back lighting I will stick with the AMDJ LED Pros simply because they look nicer (to me) looking into the can than the Design 36. The bulbs are smaller and therefore "blend" easier than the large bulbs on the Design 36 I find. By the way, I am figuring on a max stage size of 16'x24' for my design.
If you're dead set on either the Wiedamark or the AMDJ LED Pro for all of your PAR cans, I think the LED Pro is a better light, but you may need just a few more to cover the same amount of stage. Just my $0.02. Good luck!