I'll have to agree with the other two posters--
DSA is the best, both their Factory SA-58's and their Stg-58 "kit" guns. Both of these are "factory guns".
The custom gunsmiths mentioned before are even better--the fit and finish will be excellent, and the final result and finish will be better (by a little bit, at the very least) than the DSA--HOWEVER, they are custom gunsmiths, and will either assemble your gun from your parts (so you need a good quality kit and a good receiver), or they usually have some in stock. You will pay additional for their services--not a whole lot more than the DSA kit gun, but you definitely get what you pay for.
One additional thing. FAL stands for (in Belgian) Light Automatic Rifle. FN is the name of the company ("Manufacturers National"). Asking which FN FAL is best is like asking what brand of Colt AR-15 is best.
AFARR