Either way gains are possible.As long as the muscles are being forced to adapt I don't see a problem with either. I personnaly like the fullbody workout, sometimes I turn it into a circuit for a cardio work out as well. But I've also know some guys who work a 5 day split and look fantastic.

I think I will incorperate a push/pull split but I really want to set aside a day for just core work as well.