Can't go wrong with either one. Both are backed by excellent warranties.
Look at the reticles, see if the extra elevation travel on the MK5 is really important to you now, or potentially in the future. The MK5 windage knob is capped, that slows some people up. Little larger eyebox on the AMG for a given magnification then the MK5. I've owned both at the same time, I only own the AMG now, my personal preference between the 2.
I've had to use warranty for both Companies, they both handled things excellent. Vortex did turn it in 5 business days including shipping to meet a match date. Leup was 4 weeks.
Both are excellent optics, you can't make a bad choice.