Was looking at various red dots for my kids ARs. I was looking at the newest version of the Leupold RDS that's similar to an Aimpoint Pro. Is there any real advantage at this point to goi g with an optic like this with smaller optics around the same price point such as the Holosun 507 series or Sig optics?

Me personally I have not found any specific advantage or disadvantage to size of the housing. It has always looked a little weird to me when I tee up an RMR on a rifle (as its what I have in inventory and sometimes do), but in competing I have not noted any difference. That said I happen to like a bigger window on rifles. Not at all related to your question, but I hope people start to shun buying chinese anything.

I didn't care for rmr size optics on a gun either. Now I have an RMR on 2/3 of my HD guns. The 3rd having a T1 micro. All 3 also happen to be SBR or pistol configuration and it helps keep the weight down. I'm partial to the Eotech reticle and have some Holosums performing well on some shotguns. I'm hoping other companies get on board with this reticle but as of now it is what it is.

It's really down to the Leuopld RDS Holosun or Trijicon MRO if I want to stretch my budget. The simple fact is these rifles spend 90% of the time in the safe. Eventually they'll be given to the kids but by then l, who know what kind of optics will be available.