Erm...
i wouldn't be able to comment from personal experience.
Im a very "ENGLISH" manager shall we say, whoever and wherever im managing,
4 at the back at all times, unless im pushing for an important win that im losing XD
if you got to the quarters with it then i would say it is a successful formation, however with the big teams mostly playing with packed midfields, they could easily overload your back three.
The contrast to this is, that if your team can put your attacking advantage to good use, it doesn't matter how open you are at the back!