get a Polytech, or a Norinco. They actually have pluses over the latest commercially made M1a's from SA. USGI receivers; or, forged receivers at the worst...some of them.
You may ask Sporter on this site. He's had quite a few models more than I and knows more history.
If you get into the Chicom stuff you may have issues swapping parts out for USGI, especially flash supressors and castle nuts. They spot welded a lot of them and the thread patterns may be different.
The Polytech line of M14's that one can find for around $900 area are about the cheapest option to step into an M1A/M14 style rifle.
The Polytech has a true forged and machined to USGI spec receiver.
The downfall of the Polytech is that some have had some long head space issues.
However I have never ever read or seen an example of one having a Kaboom.
Out of the box a Chinese M14 will function perfectly and will probably never let you down. The Chinese M14's also have a chrome lined barrel that is on par with a USGI barrel.
There are several M14 smiths on the net that will install a USGI bolt in a Chinese M14 to bring it up to USGI specs.
Overall a Chinese M14 with a GI bolt and some other mods is probably the closest you will get to the real thing.
Another good option is to go with a Springfield Armory M1A, preferably one that is about 10-20 years old. The older you get the more USGI parts are typically in the rifle itself.
The Springfield has a lifetime warranty. Some have had some problems with newer SA models. The problems I have seen from commercial parts are: Bent op rods, extractors flying off etc.
Other than some small issues the Springfield Armory is a top shelf rifle. The SA receivers are investment cast.
A company out of New York "LRB" does manufacture drop forged M14 style receivers. They are pretty top shelf and seem to have a good reputation at the moment.