NUS is indeed awesome as an individual university in terms of rankings. But when you compare it with top US universities like MIT, Caltech, CMU, US universities outsmart NUS in every possible manner; whether in terms of job opportunities or subject content or even practical exposure for that matter.
Moreover, on the one hand you have negligible stay back period (NUS, Singapore) and on the other hand in USA you get 3 years stay back period to search for a job.
Hope this helps. 🙂