I went with the P10C and had it milled for a RMR. Kind of an all-around pistol for EDC, HD, range fun, and will be a backup for my Shadow 2 when I shoot Carry Optics in USPSA. For the size, it does all the above pretty well.
I got mine before the OR versions of the P10C were available, but in retrospect I think I’m pretty happy having it direct milled vs OR from the factory. For me, the advantage was I had the option of putting the BUIS in front of the optic, plus I’m pretty sure the milling company was able to get the RMR to sit deeper in the slide than the OR are capable of.
Is deeper better than taller? Is direct milling better than an optics plate? Hard to say, but I’m happy even tho it cost extra for somebody to do the milling.
I suppose one advantage of an optics plate over direct mill is it gives you more options down the road if you want to try a different brand of optic. Direct milling locks you into one optic’s footprint. Sure, the RMR footprint is compatible with Holosun optics, and now there are two Trijicon models to choose from. But say I wanted to switch to Leupold, that’s a no-go for my P10C because of the way it was milled. But if I had a OR model, by changing plates (that may or may not be available, LOL) I could in theory change the plate and use a different brand of optic.
As far as sitting low... advantage is you don’t need as tall of BUIS to co-witness. You also have less height-over-bore to contend with. Probably not that big a deal as a EDC/HD gun but sometimes in competition it comes into play with NS and hardcover targets.
Lastly, do optics mounted in pockets specifically milled for that optic fare better than optics mounted via plate? I don’t have any data to suggest one way or the other. But it seems like they all break at some point, and maybe keeping the mounting screws torqued properly is a bigger factor here.
