Hi, I am German Chinese. Thought about sending our kids to local school for the benefit of learning Mandarin. But in the end they are attending the German International School. After making a list of all expenses (books, uniform, tuition, donation etc.), the difference is not that much. I spoke to other Chinese born and raised in Europe and which school to choose. Majority opted for their mother tongue (French, German, Dutch, UK). 2 of the ones who started out at local level, changed to international ones after one year, citing not coping with Chinese, too restrictive. Our local friends also told us not to send out kids to a local school. as none of the parents speaks Chinese it will be very difficult for them to cope with the curriculum, unless youa re willing to fork out money for tuition, but this needs to be almost daily in order to keep with the level.
Forget about Henry Park and Chinese Girls. As a Singaporean you already have problems getting your kids in these two. Let alone being a foreigner. I know of friends whose kid is US citizen. To enroll her at Nanyang Primary, which is also a top girls school, they had to find sponsors etc. Even though she is already attending the school for 3 years, every years the parents have to show their sponsors "gratitude" for getting their daughter in.
Another point no one brought up. How proficient are your children in Chinese, Malay or Tamil. They have to choose one of these as first language. Standards for Chinese Girls and Henry Park are pretty high. Especially Chinese. If none of you speaks Mandarin it will be very though for your kids to cope.
Swiss Cottage: they have a reputation to take in the left-over students. Reason: majority of top schools are located around Bukit Timah area. Swiss Cottage is the only other private school in this upper class area. So just for the snob appeal, instead of sending your kids to a private school in neighbourhood areas, you enroll them here. Better to say your kid goes to school in the Bukit Timah area. Secondly, a lot of the rich Chinese Indonesians "fled" to Singapore after the 1998 riots. As their grades are not sufficient to enroll the other good schools, they opt for Swiss Cottage. My friend (who is Dutch married to Chinese) took her kid out off Swiss Cottage after a year. Reason: all the Indonesians were hanging together speaking Indonesian and throwing around money.
Though the schoolfees for the local schools may look lower, please look at additional cost too. If you don't send your kids to tuition, whether they need it or not, some schools regard you bad parents. There are also the donation drives for sporting complex, computer room etc, that all adds up.
Look carefully at your expenses and see if some how you could set aside more money for your kids education and send them to an international school. We did. Gone is the car. No more dinners outside. But we do have a nice house and entertain more at home. In the end, though only here for 3-5 years, education is too important. But that's a personal view.
Good luck with this difficult issues.