While things are cheap there, your travel expenses to reach those places of your interest will cost you money. So, do not rush to those places without doing your math. Also, do not forget the exchange rates on your credit card will cost you more!
But if it is an experience, then go enjoy the trip. Factory outlets are the favorite hit by Singaporeans. But do you know that there are factories in vietnam to make cheap branded clothes for factory outlets? That is why there are so many so called factory rejected goods for Armani Exchange, Guess, and what have you. Its all BS btw. The material grade is lower and so will be the workmanship.