I reviewed the Ken Onion edition, and I was very impressed with it. The MK.2 is very similar with some very user friendly additions.
Here are the pros to the MK.2
-It is more user friendly with 2 knife sharpener settings, hunting knife/kitchen knife, vs picking an angle between 15-30°
-Less belts to cycle through making sharpening knives a little quicker
-You have 2 speeds to chose from making that decision a little easier versus having to twist a knob to figure out which speed is best for what you are doing
-The guide is more user friendly with a piece of felt to keep scratches on your knife to minimum
-Easier to change out belts
-While the features of less angle and speed selection make it easier to use it also sacrifices a little user autonomy (probably don't need the wider/narrower angles anyway)
If I were to have to chose between the 2 models I would go with the MK.2, in this case less is more.