My go to ammo has been IMI for the last 10-15 years. Shoots fine out of 85% of my rifles. Out of damned close to 10k rounds, I've never had a FTF, squibb or any other type of mishap. Most of what I've got was made around 2005 & 2012. I stopped buying all Fed/LC ammo. Just too dirty and it seems there's such better ammo out there for less money.
GGG is GTG. I'd consider it on par with IMI and feel confident it won't let me down.
I've got PRVI but just don't shoot it very often, hard to give an honest opinion, just don't shoot enough.
Lately been shooting the Geco in .223. I've been very impressed with it's accuracy and consistency. Super clean and definitely a keeper based on accuracy. I've not tried the Geco in 5.56 but plan on trying it out.
I'm still shooting Guat, Radway and SA in 5.56. Was fortunate to stack that stuff really deep.
Guns are LMT's, Spikes, Colts and Knights Armament. Barrels are 16 & 14.5. All are 1:7.
Thing to remember is it seems no two barrels are alike. Two identical LMT's one will shoot the newer .223 Geco @ 1.5 MOA all day long. The other is closer to 2.5 MOA. Yet the one that shoots the Geco not so great is very impressive using older IMI made Winchester Q3131.
Give Geco a try. Sam at SG usually has it, but has been out for a while. Hoping he's due for more anytime...I want more!