MKF looks like a significantly different movement design to me, different Mainspring Barrel teeth (shape & number of teeth) and different mainspring barrel position aswell:
MKF Date window looks indeed better... but customizing (if the JJF/PF dwo isnt fitting the mkf) i think it isnt worth it just for a better date window.
MKF is milking their 5711 in every possible way - the MKF V12 will have good lume color presumably
Good question. I wish MKF or Puretime would list the improvements that had been made for this version. Some changes can be seen in the pictures by us, the consumer, but other changes not so much. For example, did MKF improve the bracelet to be more flexible? Also it is disappointing that MKF did not correct the misspelled words "adjusted" and "cold" on the movement, which was pointed out twice in the past. MKF is not listening. Hurry up V6F/VSF/XF.