It’s just as good as the 5.56 if not better (especially at longer ranges).
Friend of mine can hit a refrigerator sized target at 700 yards with it using iron-sights. I’ve never tried that though.
The rounds are smaller. 53 grains to 70 grains.
Nice.
For your average un or semi trained grunt, or an older civilian like myself, I really like the simplicity and tank like reliability of the AK platform. The 7.62 is a bigger and slower round, but some guy like me who would probably never be seriously going out past 150 yards.....
5.45 X 39 on an AK platform sounds like a nice match.