Mil ranging (or MOA ranging if you swing that way) is a legacy skill that doesn't often come into play any more. Range finders are cheap and plentiful. Many matches give distances to the targets (not all, I know). Today, in 2019, the reticle is primarily used for holdovers and wind correction. It boggles the mind to think that one could know how to use one and not the other. It's analogous to saying "I can measure in inches using an inch ruler, but can't measure in centimeters using a centimeter ruler."
Very few can shoot the difference between 1/4 MOA and 1/10 MRad, so picking one based on the fineness of graduation is dubious at best.
Ballistics calculators output both, so you can have a calculated and confirmed dope chart in either measurement. Dialing corrections is as simple as looking up the range on the sheet and making the corrections on the scope and/or holding off using the reticle.
Why pick one over the other? If you are shooting by yourself, IT DOESN'T MATTER. But, if you are shooting with a group it might.
Do you or your shooting buddies have a spotting scope with a ranging reticle? You might want your scope adjustments/reticle to match that reticle. What reticles/adjustments are in the scopes of the people you shoot with? You might want to be able to "speak the same language."
Do you (or are you planning to) compete? What adjustments/reticles are common in your chosen discipline? If you suck at reading wind, you might want to glean info from others in your squad quickly. Here's a hint- in PRS style matches you're more likely to hear wind calls in amount of hold off, not mph. As often as not, hold off is announced as "left edge of plate" or some other measurement agnostic description, making MOA v Mrad moot for this point. If you're really good at reading the wind, you might want to confirm your wind calls with others in your squad efficiently. This goes equally for elevation adjustment/hold overs.
Do you never plan on ever using info from others? Pick whatever you like, but you still might want to go with the majority because plans change.
If none of the above applies, you can always fall back on "MOA is easier because I think in inches." If you do this, please start a new thread- announcing your choice- in The Bear Pit...