I think highly of the SA receivers. I am about to rebarrel for the second time a rear lugged Super Match that I purchased about 1992. I won my last leg and a Regional Gold with a SA factory Super Match, I consider them fine, reliable and accurate rifles..
You do have to watch them, the old match rifles have screws “unitizing” the gas cylinder. These screws will get pounded loose in time. I think unitizing the gas cylinder with welds is the better way to go. Also have had a unpinned op rod guide come loose. So I peened the barrel spline and drilled and pinned the operating rod guide myself. That has held for about 4000 rounds.
The Springfield Armory rifles were the most common civilian version of the M14 on the firing line for years, and they are well thought of by those who used them. Most of the match rifles of this period used GI parts for the trigger assembly, bolt, operating rod, gas cylinder and flash suppressor. If equipped with such parts you had a rifle that would shoot a very long time.
A bud of mine when through six barrels on his SA M1a and it developed a crack above the bolt release. Just a little half moon worth of material cracked off. The rifle was functioning fine, but we harassed him about the duct tape holding the chip on. Even though he had gone through six barrels (about 30,000 rounds) and the receiver was at least ten to fifteen years old, SA replaced his receiver for free. I consider that good customer service. And considering that my friend shot at least $15,000 worth of ammo through that receiver, he got good service. By the way, all the other parts, gas cylinder, bolt, trigger group, flash suppressor, were checked out and were good.
I do like the fact that SA has added material to the sidewall of the receiver. The GI configuration of receiver was lightened as much as possible to meet a unrealistic weight requirement. If a M14 receiver is going to crack through fatigue, is will be in the sidewall. The bolt goes back and bounces off the rear of the receiver, in time all those impacts add up.
Reinforced SA sidewall
I have been able to examine a couple of LRB receivers. (LRB OF LONG ISLAND, INC. 32 Cherry Lane , Floral Park , N.Y. 11001
Phone: 516-327-9061) Lou is making an outstanding forged receiver out of 8620. A bud purchased a rear lugged version, and I got pictures. I like that LRB drilled a hole and supplied a screw for the lug. Overall the receiver looked great, but the gunsmith will have to tell us how well the parts fit on the rifle. Lou is cutting these to GI dimensions and you can see in the sidewall picture that his follows the GI contour.
These are very expensive, but they are the only US forged receivers made.
LRB Receiver
Actually, not sure I'd buy one if I could, though not due to lack of quality. 
