The OICW has been put on the backburner, from my understanding. Too heavy, and the 20mm ‘smart round’ doesn’t perform as advertised.
The Army is testing 6.8x43 versions of the M-16, M4, and the HK XM-8 (which formed the 5.56 portion of the OICW). 6.8 is already in use by benchrest shooters. Of course, one day, the Army will see the light, and just bring back the M-1 Garand. Good enough to thwart the Nazi and Imperial Japenese warmachines, good enough for Al Queda… 
As for the FAL, it is (was) one of the most widely used rifles in the world. Nations that didn’t use the AK generally used either a version of the FAL or the HK G3. Depending on the variant of the FAL in question, many had grooves to channel away debris, and they all have an adjustable gas system that allows you to shoot through some nasty conditions. Some of the many factors that allowed the FAL to flourish.
Bottom line, of course, is that comparing the FAL (say, the L1A1), to the AKM to the M-16A2 doesn’t provide a clear picture of which is better.
-The AK is the simplest, and probably the most reliable, but is certainly the least accurate. Also, the 7.62x39 ball round is not exactly God’s gift to terminal ballistics.
-The M-16xx is fairly reliable, pretty accurate, but the same 5.56x45 round that makes it easy to shoot, also limits its effective ‘engagement envelope’.
-The FAL fires among my favorite rounds, the (by todays standards) powerfull 7.62x51. It is fairly accurate and reliable, as well.
Pure personal prefernce knocks the FAL down towards the bottom of the list. I prefer the M1A. But as long as you are in America, and not in California, go nuts, and buy one of each. Over the past few years, I did. 