In my opinion, this a balance formation in term of attack and defend, most of the time you can easily out score your opponents. However, there is hole in the middle and that is a disadvantage about this formation. About 4 months ago, I have played against it once in CL. First leg, I lost 1-0 with diamond. At home, I beat him 3-1 by using 3-2dmr/dml-2-1-2 (one blue and one red on MC), also after 75', I put one of my MC at dmc position and sub him with a right personal...so that no one plays out of his position.

If you ever used it, there are few formation that you need to pay close attention to, watch out every formation that attack to middle.
3w-1-4-2
3w-1-3n-1-2
3w-1-3w-1-2
4-1-3n-2
4-1-2-1-2 diamond
4-1-2-3
3-3w-1-1-2 or 6-1-1-2
3-2(DMR/DML)-2-1-2