Thought i would add to this as I have just returned from there.
1. Prostitution is legal provided it's in the red-light district of geylang area. And many Singaporeans are very open about this. Strange how rigid and conservative most things are in Singapore and then they have this thriving district.
2. There is a forum called sammyboyforum which has advertisements and reports. They seem to be the best source of legal and illegal options.
3. I had a small sampling of both. No review, as the ladies turn over so quick it would be pointless.
4. The 4 floors of whores...meh. It was fun for the first 30-45 minutes. Then it was just an overwhelming meat market.
5. Careful of the ladies walking the streets, especially by the 4 floors. They're more than likely tranny. I love a good session with a tranny, but I like to know what I'm in for beforehand. How do I know this? Just ask them, they'll show.
6. Nearly all the ladies in Geylang will be SE asian. Lots of Malay, Vietnamese, Phillipines, Thai.
Check out the above forum as it will have up to date info on all the happenings in Singapore.
Good luc