I've considered obtaining an AK clone as a plinker (the most obvious use)/home defense (the use I hope never happens) rifle.

Looking at the various sites I find a bewildering array and variety of AK clones. What's the difference between a Polish and a Bulgarian and a Chinese made? What are the choices for calibers/chamberings?

It makes choosing a 1911 clone look easy.

Is there a central repository for information that is up to date, authoritative and written so the information impaired can understand it?