I have not shot a AR-10, but I do understand that match versions of the rifle are very accurate.
I have shot tens of thousands of rounds through Match versions of M1'a's. These are superbly accurate, wonderfully reliable; match M1a's dominated the firing points at Camp Perry for years. My rear lugged M1a's just seem a tad more accurate than the non lugged versions, but it could all be that I am justifying the extra expense by thinking they are more accurate.
You cannot go wrong with a Match M1a.
I would recommend one of the LRB forged receivers. I was able to inspect one, it is a precisely built receiver. There is nothing wrong with a SA receiver, all my rifles are bulit on them, however the LRB is the only forged M1a receiver made, will be built in less quantities and will therefore command a collector’s premium when it goes out of production.