I've never been to Singapore, but I just used Agency Atlantic while in HK last week and had a great time.  They have ladies that often tour Singapore.  You might want to check them out.  http://www.agencyatlantic.com/

The appeal of Singapore is the continual turnover of fresh talent from all over Asia, so reviews would be pointless. By the time a review is posted, she may well be gone. The exception would be some general comparisons of the brothels is Geylang, which I believe you can find on the international sex guide forum.