Another range of consideration would be Saber Defense (personally this is a hidden gem of a AR especially at it's reasonable price point) LMT, Daniel Defense and PWS.. PWS for a piston system if that's a realm of consideration. While what Hoser says has merit regarding the piston systems, the systems themselves are evolving to utilize the very proven AK action. I've got a PWS converted Saber Defense rifle that I'd say is as good as anything else in it's comparable price range ($1500-1800).

The ACR is a very interesting weapon system, but I'd again agree with Hoser, it needs time in the market and the rest of the production bugs worked out. Not to mention the accessories/after market parts vendors need to see enough value in ramping up spares. The same applies to the SCAR though we're starting to see several vendors step up to make aftermarket parts for the SCAR platform. Still woefully short on options in the replacement barrel arena for both.

You won't go wrong with the mid and upper tier manufacturers. With the expected use you've outlines, I think that any of the manufacturers that folks have thrown out will more than meet the need. Just don't expect to only have one AR by the way.