From my experience, b-school adcoms don't look at TOEFL writing scores as much as they do
AWA scores.
You definitely do
NOT need a 6.0 to get in. I've had many students get a 5.0 on the TWE and a 5.0 on the
AWA and get in to great b-schools. I think the reason that they get the same score on both tests, even though the TOEFL is easier, is that many smart folks simply spend more time on the GMAT than they do on the TOEFL and don't learn how to write a TOEFL essay.