Hi Sunnie Gal, I'm a FTWM. For my case, my girl was initially taken care of by my mil, but when my girl was about 6 mths old, my mil's leg started to give her problems, so in the end we sent my girl to infant care, as we really didn't like the idea of having a stranger in the house.
We did worry about her getting sick often, and yes, she did catch a couple of colds once in a while, but we were thinking, she'll be going to child-care later on anyway, so might as well let her catch cold now and build up her body immunity. And by letting her play with other babies, she can socialize and also learn things from other kids, like when she sees them crawl and walk, she'll want to learn to do that too. And there is probably less separation anxiety from mummy and daddy when she goes to child care in future, cuz she'll be already accustomed to the infant care system.
But having said that, if you really are lucky and do get a good maid, it's really much more cost-effective than putting your bb in infant care, and there is also an extra pair of hands at home to help with household chores. Plus, if bb gets sick, either you or hb will have to take leave to stay home to look after bb, and the infant care centres also have 6 designated holidays (excluding public holidays) for staff training and cleaning of the centre etc, so you will have also take leave then.
But I do agree with fuyutsuki that it would be better if there's someone at home to watch over the maid. We would have done so to get my mil to watch over the maid, but given my mil's personality, we were worried that conflicts can happen very often between her and the maid.