Personally, I find Mils easier to use and I find that being a base10 system, it fits with the metric system "better".. The topo maps I use are metric and thinking in terms of 1/2Klick, 1Klick, 10Klick ect comes naturally..

I don't use the reticule for ranging so that's not an issue for me which ever system I use so really it comes down "familiarity"..

I think the one thing to avoid is a scope with mixed Units as is pretty common for some strange reason.

Go with MOA/MOA or Mil/Mil and just get out and shoot..