Firstly, it depends on the hospital or gynae of your choice. There are gynaes that are in government hospital like Dr Suzanna in KKH, Dr Citra in NUH while some private Dr are in TMC,Mount E, etc. Then, the packages each of the private/gov. hospital have for private patients. What are the breakdowns for pre natal, labour, post natal checks. You can choose gynae based on recommendations by friends/family/experience. End day, it is also subject to gynae's availability till your EDD and if you would like them to be your gynae.
Most people choose gynae because they prefer the particular gynae or they prefer to have just one doctor overlooking all of their baby's need and them.
Hope this helps.
itsallabout_mytwokids