It's the same animal, just a different round. I like it better, it's more accurate (if you can even use that word associated with an AK) and the round has some wicked characterisitcs after it hits human tissue. If I remember correctly, the bullet can do almost a 90 degree change in direction after impacting the human body. The Afgan's gave it a spooky name during the Russian-Afghanistan War, but I can remember it.
As for the CAR15/M4 type weapons, they're great for urban warfare, but it would not be my choice for an engagement more than 100yds. Most people know that the 5.56 round has a bad rap for killing power, but that is beyond to 200 yard range (for the M16A2). After 200 yards, the 5.56 loses a lot of its energy and loses its ability to fragment after it hits tissue, making it much less effective. When you switch up to a 16" barrel, you lose about 500fps velocity, and reduce the fragmentation range to around 150 yards, thus making the weapon less lethal. But it DEFINATELY earns its keep in close quarters engagements.
uke: 
