My analogy to the non-matching turrets and reticle has always been this.

You're cutting in base board in a room in your house. You measure six walls, with an inch tape measure, you write them all down. You sat down your inch tape measure and walk outside to your miter saw. On the saw is a metric tape measure. You can cut your base boards, but you have to convert your notes in inches to centimeters.

You are zeroing a Mil reticle scope. Your first shot is .8 Mil left and 1.2 Mil low. In order to adjust in MOA for your turrets, you multiply Mils by 3.43

If your turrets were in Mils, you would dial right .8 and up 1.2. And that holds true at any distance. We are getting DOPE, and at 600 yards you hit steel, but .2 Mil low. OK, dial up .2 Mil and shoot again. I go through this each and every week for someone else's rifle/scope combos.

Does this assume you are measuring impact with the reticle? I get tempted every now and then to try Mils on one set up, to see if it would work for me.

Yes measuring impact in Mils.

The Mil Mil scope just makes life easier. Your reticle is your ruler. I can zero one with a blank sheet of white paper. No grid lines, and not even a point of aim.

If I hold 2.0 up from the bottom edge of the paper, and 2.0 right of the left edge of the paper and fire a shot, I can measure where it landed. Dial the correction, and now my point of aim is the lone bullet hole.

On the perfect rifle, perfect ammo, perfectly tracking scope, and perfect shooter, zeroing is only two shots and it is over.

When I'm getting DOPE I dial for a distance, I shoot. I note where it landed versus where I was aiming. I write down the information as needed. If I dialed 1.8 Mils for 400 yards, but it landed .1 Mil lower than where I was aiming, I write down 1.9 as the DOPE. Move on to the next distance.

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I suppose Leupold is making what sells, and they assume most hunters zero at a target with 1" grid lines, they see their impact and dial 7 & 16 clicks. You could still use the Mil reticle for holds, and MOA to zero, right? I do like that with Mils, you can make a shot without dialing which I do now. I missed an opportunity at a good Mule deer buck at what I had ranged at 504 yards this year. Had I gone right from the range finder to the scope, rather than dialing, then to the scope, might have made a difference. I'm light years from being able to use a Mil reticle to range based on an assumed torso size.

If you like MOA, your can do the same thing. You just need a MOA reticle AND MOA turrets. Measure the impact with your MOA reticle and make the appropriate adjustment.

Like Jason, I just prefer MIL. I like the simplicity of everything based on 10.

Yes you can still use MOA to zero, and then cover the knows, never dialing again. Leupold and so many other optics companies act like they don't have any shooters working there. If you have to buy 1 MOA grid targets to zero, that's not the end of the world. I'm just saying there's an easier way.

Making holds is for precision, if you get good at making holds. And it isn't difficult with some instruction and practice. It is also for speed. Many, many animals I've killed as far out as 540 yards just making a hold.

My bad misread 6mm, thought it was 6.5.

I am in the minority on here but for a hunting scope I prefer a second focal plane and a bold reticle. In low light the reticle size is constant regardless of power.(it remains bold at low power) At 61 my old eyes do better with that. There is a down side to that as well. A reticle with subtensions for holding wind is almost useless in a second focal plane scope. As you change power, the subtensions change. In that respect you can either dial wind or use Kentucky windage or only run the scope on its highest power(which is useless in a variable power hunting scope). In a second focal plane scope a duplex is not giving up much for what a reticle with subtensions buys you unless the scope is on maximum power. Not nearly as precise but plenty good for me shooting deer vitals out to 400 yards. I rig hunting rifles second focal plane and moa. The money I save on the best turrets and reticles I spend on glass quality. They are not as precise but that has never cost me an animal out to 400 yards. Judging holds to correct for misses has never been an issue for me while hunting at 400 yards. Shooting the animals I hunt is primarily a one shot proposition.

For a target gun where low light is not a priority for me, mil/mil first focal plane scopes are hands down my choice for the reasons already mentioned by others. Holding wind on the reticle just works better for me. Dialing elevation and holding/dialing windage and judging distances is so simplified in first focal plane mil scopes. The subtensions are consistent regardless of power setting in a first focal plane scope. MOA/MOA will also work but it requires more thinking, at least for me. If it were not for the fact that the lower you turn the power the finer the reticle gets, first focal plane are all I would run. If you want a rifle to do both, first focal plane is the way to roll. First focal plane scopes with a useful reticle make precision at distance much simpler. I just never found a FFP scope that the reticle did what I need in low light for the hunting I do well enough to rig my deer rifles with one.

Which ever choice you make, you are giving something up. Scope choice is personal and about priorities to me.
Good luck deciding which direction to go.