AN-94 OR AEK-971?

1 - All guns in our beloved BF3 game require some practice to fully master them.;-)
So go ahead, test them out yourself and experience which work the best for you personally.
For example: play one night with one gun, play the other night with another gun
Learn all its behavioural treats, recoil, rate-of-fire


2 - Other option: Search Youtube for dedicated BF3 Weapons comparison videos
That material can give you some more background on both guns