I've been hovering and div 4 and 3 for quite a while now. I come across this formation a lot. After really struggling against variations of 433/4321 using lots of different formations, I tried 433(4) out myself.
It's success is because it suits any playstyle, whether your intention is possession or exploitation and also that it can be played on ultra defensive yet still feels exceptionally attacking.
I expect you'll all be seeing a lot of 433(4) for the duration of FIFA 16!