My MK was set up for 6+ and so I set up my Naza Hexa the same way. The disadvantage is when videoing, the front boom sometimes comes into the field of view. This would be minimized with the 6x. Right now I have no gimbal on my Naza so it does not matter.
I just got mine a few days ago and I set X6, i just thought it looks cooler flying that way. Plus I can wedge my contour GPS helmet camera in between the top an bottom frames and that wouldn't work in forward flight with +6