The Galil is a Kalashnikov. I read a interview SOF did with the designer years ago....he said based on feedback from front-line troops (who considered the FAL unreliable) they decided to make what is essentially a high-grade copy of the AKM in 5.56 NATO. The prototypes even used re-worked M-16 barrel blanks. They only dropped it for the M-16 because the M-16 is cheaper for them because they get them as foreign aid from us.
The Galil is heavily inspired by the Finnish Valmet RK 62 which itself is derived from the AKM, thus the Galil is a few times removed from the AKM, although the inspiration is clearly evident.
That said, it still doesn't take away from the fact that militants throughout Colombia use the M-16 whenever they can get ahold of them. Many of the right-wing paramilitaries are using the Galil because it has largely been phased out in Israel and there are large quantities available. When you have limited options you take what you can get, but most people who have the choice, go with the M-16 for obvious reasons.
The M-16 is a better rifle than the AK-47 because the M-16 was designed first and foremost as a rifle that just happens to have an automatic fire capability. The AK-47 was designed as a shoulder fired machine gun that could also be used in semi-automatic mode, although the primary intent has always been fully-automatic. As a machine gun the AK family function better than the M-16 but as a rifle, the M-16 is easily superior to any AK variant.
If the objective is to spray round after round, pausing for only as long as is needed to change out the magazine, an AK variant may be the choice to go with. If the objective is to deliver precise and accurate fire, out to distances of 500-600 yards, then the M-16 is the obvious choice.
The M-16 is also much easier to disassemble and clean, and while it has some issues with jamming (most often due to inferior magazines, inferior ammunition, or improper maintenance on the part of the user), the AK variants seem to have a propensity for stove-pipe jams, particularly during extended periods of automatic fire.