I have a co-worker who has put together 3 AR-10 rifles, one in 45 Raptor, one in 45 Bushmaster, and one in 308. He has not had one single misfeed with any of them. However the case of the two 45 caliber rifles he purchased rifled barrel stock and cut the chambers himself, so that may provide one benefit not available to most. In the case of the 308, that was assembled using a completely finished barrel with extension.

I really don't see any reason why an AR-10 would not be reliable as long as the correct magazines are used and it was put together correctly with well matched components.