I've always played 4-4-2 as it has a great balance of attack and defence.

I think it depends on what players you have in your team. I purposefully look for players that will fit in the 4-4-2 mould as that is the way I like to play. The only exception to that is I will have 1 player who can play AMC so I can move to a 4-4-1-1 if needed, but other than that I NEVER change from 4-4-2.

I'm level 27 now and I don't think I've ever used a player in the DML/DMR or AML/AMR spots other than when rotating in friendlies. I've seen lots of other managers mess up their teams and runs by trying to come up with clever formations or use formations to counter other people, where as I've always stuck to my guns and kept it simple. It seems to have worked for me.