I also have the similiar problem due to I have 2 maids, 1 - work for 4 years, contract expire next year April, the second - 4 months. And I want to select either one in next year. The old one, my elder daughter love her very much, and me is ok, not to bad and she is very good to take care my kids but I don't like her always advance salary and her husband long time no jobs, she always loan in finance co (but is ok, my husband is working in that co, every month I deduce her salary to reply the loan). But many my friends like her, due to this job is her first domestic helper job, previously she is a nurse and good english standard, she is recommend by 1 of my philipine friend.
The new one is working in Singapore over 9 years, quite experience and also recommend by my existing maid. But due to her experience, sometimes I tell her to cook what kind of food, but finally total change, she will decied to cook what and she work very slowly. But it is ok, not to bad. If next year I not continue the contract with my old maid, no need to pay the long service bonus.
So I don't know how to do but have at least 6 months for me to think about this.