I gave birth to triplet in June 2009 in QEH.
They all stay in Newborn Intensive Care Unit (NICU) at the very beginning due to light weight.
I think their NICU is very good and experiece. I also saw babies transfer from private hospital. Of course, for mother, u still need to stay in those BIG room with limited service due to lack of manpower of the HA.
I think for the sake of bb, esp for twins/triplet, I strongly suggest u to choose QE rather than private hospital. Mother may not be so comfortable but its worth for bbs.