Yes, AK is underused, but the AK is amazing, try it out.
I use Drake's AK, and everyone who complains about RoF blindfire has never played with me
Drake's AK? Nice. I only have one character AK and it's Eddy's. Pretty good long-range. Not as far as a sniper, but if you can hold the recoil/have twitchy thumbs, you can do well with long-range, especially with the Scope Zoom.
Oh, dude. You should see me with my Marlowe loadout. RoF blindfirers complain about me.
EDIT: The AK is more underused than the horn in GTA games.
The AKs are the only character guns I didn't unlock any of yet
Although when I do use it, I use weapon expert and use accuracy + scope zoom. It's amazing and i love it! Its fun taking down those people who dont know how to use FF.