I'll add to this....
I love the AK for many reasons:
-It's sexy. Some think it is ugly though.
-It's rugged and durable. It will last forever, and parts won't need replacing because they break. They'll need replacing because you lose them during cleaning. But there aren't many small parts anyways (no cotter pins and such).
-You can bounce it down a cliff, hike down and pick it up, and it will function just fine.
-It's very simple in design, with fewer parts than other rifles, and the 'clearances' allow for much grime and muck without fouling up the action.
-You can dig it out of frozen mud and it will simply shrug it off and fire.
-It's accurate at all "practical" combat distances.
-Cheap to mass-produce.
-Requires little training to use.
-Easy to clean. I can get my AK from filthy to clean and lubed in 10 minutes. My AR and SKS take me 30-45 minutes each.
-There's something about steel and wood that plastic and aluminum can't match.
-I can trust my life to an AK, even if it was dragged through the dirt across Zimbabwe.
-It is the weapon that has brought many people their freedom, and allows small groups of individuals to take on oppressive governments.
The cartidge itself: the 7.62x39mm will shoot through walls, it will shoot through cars, and it will put a man down very quickly. It is effective at all 'practical' combat distances. You can take a deer with it. The taper in the case makes case extraction easy. It's also economical to produce, cheap to shoot.
The AK used to be an obsolete design, but folding/collapsible stocks and accessory rails have made it as capable as an AR-15/G36K/whatever-modern-design. It is viable as a 21st century rifle. It will be a force to be reckoned with for decades to come.
I like how much "bang for the buck" one can get with an AK. It's a good utility rifle, reliable, packs a good punch, and customizable to the users needs.
Personally, I think the term "assault rifle" is negative. I never use that term myself.
That said,
I like the AK. It keeps me safe.
An AK a day keeps the zombies at bay.
My WASR-10: