Depends on what you like to do this place is a big tourist spot, If you like Diving, fishing, water sports, hiking, boating, dolphin watching, water parks, dinning, shopping Guam is the Place for you it's kind of a mix between the states and pacific island culture. Maybe I'm jaded because I now live here
Guam Visitors Bureau
I would highly recommend Singapore much more cultural diverse things to do there and everything is bigger and better, Guams still a little 3rd world in some things. But Singapore is Awsome.
Uniquely Singapore - The official website for tourist information on Singapore