I really can't comment on this objectively as I have almost no experience with the FAL and relatively little experience with the M1A.
My M1A is a stainless/synthetic "Loaded" series. I paid about $1300 for it a year and a half ago. With the exception of a single Type-57 mag, it has been flawless through about 500 rounds. I've shot it with iron sights out to 600 yards. Though it has only had M80 style FMJs run through it and has never been scoped, it constantly amazes me with its accuracy. People here might be tired of me saying it, but it strikes me as the quintessential "Rifleman's Rifle." Everything is where it belongs, it has excellent sights and a great trigger, and just feels good. It is a delight to shoot. I love that rifle.
That said, I am saving up for a DS Arms Para FAL. With the options I want on the rifle, it is looking to cost over $2K and take several months to get to me even after it is ordered. Handling FALs in various pawn shops and such, the FAL feels solid and pretty well balanced, though I might have to give the edge in ergonomics and control placement to the M1A. This might be because I shoot left handed, however. While the sights and trigger on the FAL are serviceable, and the FAL's accuracy is adequate, the M1A has better sights and trigger, and is likely to have an advantage in accuracy. Judging by reputation alone, I would give the reliability advantage to the FAL.