So much misinformation, so little time...
I own examples of DSA's SA-58, STG-58, and "IMBEL Rifle." I also own several FALs built on IMBEL receivers including early Century product (both metric and L1A1 flavors) and two gunsmith builds. And I even own an Entreprise. Guess what - all of those FALs are just fine! The nicest of the bunch is a tie between any of the DSA rifles and one of the gunsmith builds, but all of them shoot well and function reliably.
Recent Entreprise FALs are fine, definitely better than recent Century.
Century's early FALs built on IMBEL receivers can be excellent. The receiver is perfect and it all depends on the parts kit. Reassembling an FAL parts kit onto an in-spec receiver is so easy, it was a common basement hobby for much of the 90's. Meaning that even Century can do it right. I would avoid later Century FALs built on their US-made receivers.
DSA is, however, head and shoulders above those brands for current production, and has the best receiver ever made for the FAL. The DSA "IMBEL rifle" (which is IMBEL parts on a DSA receiver plus DSA 922r compliance parts) is a great FAL and about the best deal going. I would recommend it over an SA-58 unless some part of you just has to have an all-USA rifle.
The best FALs you can buy regardless of price are probably (1) original Belgian FN production rifles imported before 922(r), and (2) gunsmith builds from Arizona Response Systems. However, any of the DSA products is going to be about 99.5% as good as those two options, and much easier to find and generally lower cost.
FAL triggers are generally poor, similar to stock USGI AR-15 triggers, but far harder to improve than AR triggers. This is just part of the platform. DSA offers two options to consider if you want a better trigger, but if you really care about that, do yourself a favor and get an M1A or AR-10 instead, you're likely to be happier in the long run.