I delivered at NUH. Main reason is because of the gynae I wanted. Other reasons include the excellent neonate doctors/services, the fact that private centres refer complex pregnancy cases there (so I might as well just go there straight), and some familiarity with the place.
Other things you may want to consider... distance from your home/workplace, how long you’re willing to wait to see your doctor (in general, private centres have shorter waiting times), whether you want a package for your antenatal visits (eg. Comparing KKH and NUH, only the latter has an antenatal package from 22 weeks, if I’m not wrong)