I have owned several M1A's over the years. They have been 100% reliable with the exception of a loaded w/stainless barrel that would not chamber a round, even though there was a tag on it that stated the headspace. Needless to say I was disappointed but SAI did fix it on their dime including shipping both ways.
That was the only one I have owned that had all commercial parts rather than GI. Of the two I now have one is all GI except for the barrel (which is a Wilson and accurate as all get-out) and the other one has a commercial trigger group. Both are very accurate and have never fail to go bang when I pull the trigger.
I would stay away from Smith Enterprises rifles. While they do make a decent rifle, their customer relations leave a lot to be desired. If you don't believe me, check out the "I need a Lawyer" thread on the M14 forum.