I certainly like my Rock River Arms LAR-08 308 16" Bbl. AR. It is a fine rifle and I have even used it deer hunting in the past. It also is scoped and is a 1 MOA Rifle at 100 yards. Nothing at all wrong with it. However I have 2 Springfield M1-A rifles. One is a M1-A National Match, scoped and the other is the Loaded Model with Iron Sights. As much as I like my RRA AR 308 if I had to make a choice of only one rifle it would be the M1-A.
I carried one in the Army before I was issued the AR and then I shot two M-14 Match Rifles while on an Army Rifle Team. Just love the M-14/M1-A weapon and as stated if I had to chose one it would be the M1-A even though I like the RRA 308 AR very well. I have shot the scoped M1-A at 1000 yards several times and it did a respectable job. Not the most accurate rifle at that distance but still did as well as expected. So if you are only choosing one weapon I would say the M1-A in the NM or the Loaded Model!
Here is the M1-A NM and the Rock River Arms LAR-08.