The FN-FAL (which, if you want to really split hairs is considered a battle rifle using the 7.62 NATO cartridge) is a much nicer shooting rifle than the M14. Possibly a finely tuned M14 will out-shoot it, but between the two, I much prefer the FAL.
BTW, I own a full-auto M-16 (liscened with the BATF), FN-FAL, and AK47. I used to own a Galil and MP 5. My father owns two FAL's, several M-16's (a M-16A2, a AR-15 Heavy Barrel, and CAR-15) two AK's, used to own a M-14, HK 91, HK 93, AUG, and over 20 other full-auto machine guns. I have fired thousands of rounds through these guns. Am I an expert? Nope. But I have shot them all (and used them in competitive scenarios) enough to have formed an educated opinion.
But opinions are like other things. I love the FAL, my dad prefers his CAR-15 and a two friends of ours who are Federal LEO's like their HK's.
But, none of them would choose the AK as the one gun they'd take to war. It's true the 7.62x39 cartridge is more powerful than the 5.56 and it's almost impossible to break. However, it is crud, kicks more (especially full auto) than a M-16, isn't as accurate, is noiser (the dreaded "AK Clack" when you take it off safety) is basically the inferior weapon. Like I said, you can't break it.
Also, there are several reasons why the US went to the 5.56 cartridge (I don't know if they have been mentioned here). It was thought the troops could carry more ammo, handle the recoil better and that it was better to wound the enemy than kill him.