I'll do my best to let you know when my 10x 42 Merlin gets here.
As far as I know, the spacing for the mil dots is 3.5 or 3.6 MOA from center dot to center dot. I belive instead of the dots, the MP20 used a hash mark.It looks like the hash marks break each Mil into quarters. Is there an advantage??? . Is the MP20 spaced exactly one mil apart?? I don't know yet.
The Mil dot system seems less complicated for ranging, yet the MP20 seems to be more user friendly for holdover and hold off.