Well the more I thought about it, I went and ordered one of the uppers linked above with the Holosun 507c X2 for $419 plus a Dagger lower for $99. Can't get into a Glock MOS for that plus I like the 507C, I've got one on my 686 and had one on my G45 MOS, never had any problems with them and the window is a bit bigger than the RMR.
The Aimpoint ACRO P2 is probably the pinnacle but it's wider than the frame and I'm not sure I'd like that, plus no one has a deal on the right now. If I find I like the dot, I've got a spare G19 I will have milled later. But for now this is too good of a deal to pass up.
