Apples and Oranges.
I have both, had an AK. All of them have pro's and con's and at the end of the day its trade offs and personal preference. I shoot comp and for most people that means speed, speed, speed! I cannot for the life of me, reload as fast with the 14 as I can my AR. That being said, I can't nail the long shots with that AR anywhere near the precision I can with my 14. One is a heavy, full figured lady that like stability and the other is a slim athlete that wants to be shot fast.
Given my druthers I'd sell everything before I got rid of my 14 but I do like having both.
As far as optics go... That is all personal preference and intended use. For 3 gun use I would keep it on the small side, x4 max and I prefer fix powered scopes. If you are just plinking or thinking about indoor use, then a red dot is the way to go. My AR has a red dot but I run my 14 open sighted.
Cheers!