Which are the advantages of incorporating in Singapore vs USA/Europe?
It depends on what you are looking for.
The main differences come down to:
-Payment processing access
-Where you can open bank accounts
-Regulator (if you need a financials services license this will be very relevant)
-Tax treaties (if you need that, depending on your situation, the tax laws of where you live etc.)
Your question requires a more complex answer than you would think, because international tax law is complicated. However, if you research each of the points above, you'll get a clearer picture of what the advantages are, which is usually not that clear-cut.