Been shooting AK's for a bit over 30-years, and thought I would add some more on recoil.
While all of my AK's throw the spent cases much further then any of my AR's, I do monitor my AK's for recoil pulse. If the recoil pulse is very harsh, I will change the recoil spring. AK's with enough rounds fired should have the recoil spring replaced as the springs are a wear item. For me it is a matter of feel not number of rounds shot.
Several years ago I purchased a new AK and fired just three rounds before replacing the recoil spring, and it has been fired many thousands of rounds since and doing just fine. My AK's do have more recoil then my AR's and I expect that, but I do not expect a sharp recoil at the end of the extraction cycle.
Hope this is of some help.
BTW, I tend to like ALG recoil springs.