I don't own one, but I shoot my AR in competition, and the M1A (when modified) is well respected for this. The M1A is a quality weapon. One negative point is that the M1A uses a cast receiver. Real M-14s use forged receivers. I'me not sure that this makes a difference, but some argue that it does. I.e., some M1As might be weak due to their construction. The excellent track record of M1A's suggests to me that this isn't a problem.
On accuracy: M1As (and M14s and M21s) are at best .75 moa (more usually 1 moa) rifles (average of several ten shot groups). This is also true of M1 Garands. This is due to all the furniture hanging on the rifle. This is excellent accuracy, but it is short of that that can be attained by a bolt rifle or AR. Accuracy work on M1As is also expensive compared to bolt guns and ARs. And they tend to loose their accuracy more quickly, requiring rework sooner to maintain top accuracy. I know this isn't what you asked about, but you might as well know . . .