@bloodycactus: lol for the DSA FailMags.
The last couple of FALs I built were on Centurys and went together well. They had a great run of them from 2004-2007 or so by Caspian Arms and they were the most in-spec Centurys I've ever seen. By way of comparison the DSA I built on last year had barrel and gas tube threads so tight they screamed, some chatter marks here and there AND needed a weird locking shoulder size to headspace. One borderline DSA does not mean that they are all bad (however there's been numerous complaints recently) and they are a good upper generally.
If I had my druthers I'd build on gear-logo IMBELs every time but those are almost impossible to find now. Century guns built on IMBEL and good Century receivers will run just fine.
Problem was Century hired people to bolt parts kits together and they were mechanics- the Century guys weren't gunsmiths and knew nothing about FALs really; plus they didn't live-fire test the guns. The buyer got to be the final QC inspector. Lots of Century rifle problems were really very minor things that any builder would have identified and fixed before it left the shop; since the Century assemblers had no real idea what they were doing they never got fixed.
There were a lot of simple things like gas piston holes misaligned, barrel mistimed, pins fitting tight or loose, bolt carrier running rough, burrs, metal flash, machining marks, and also problems with the parts in the demilled kits that were just reinstalled. Weak springs, stuff like that.