The DSA STG58A is cheaper than the comparable Entreprise model, the STG58C Government model which cost $200 more. In the long run, the Entreprise is even more expensive because they include the magazine floorplate and follower in the US parts count, which means if you want to use those $5 imported FAL mags, you need to add two additional US parts to the Entreprise. Most people opt for a US pistol grip and cocking handle, but I think you can replace the handguard or buttstock as well.
As far as quality, both rifles use the same Steyr parts kits. Given they use the same quality of kits, accuracy will be very similar. However, Entreprise uses I believe FSE US internals, which some complain are are not of the same quality as the DSA H/T/S.
And some like the DSA receiver over the Entreprise. Last I heard, Entreprise solved their production problems and their Type I's are just as good as any other US made receiver. Of course, Imbel is the standard in which to judge US parts.
Entreprise has a new Imbel rifle which looks interesting. It's probably of higher quality than the CAI and is priced at $799 retail, which I assume means you can get them for $599.
If you want the highest quality built to your specifications, then you need to look at Gunplumber or the other guys. These will cost a little more, but you get a superb rifle with a great finish.