Need help choosing undergraduate school

Background: 

Im a student from Singapore that finished conscript military service. if I stay in singapore I would be called up to serve the military 10 more times till I turn 40. studying and working overseas allows me to skip this.

Offers:
University of St. Gallen (HSG) economics

National university of Singapore (NUS) math/quantitative finance

Singapore Management University (SMU) business 

Goal:

IB in Europe or Singapore or USA(unrealistic given my offers) 

or

Hf / quants

Situation:

in singapore, SMU and NUS are targets for ib but the batches are huge with about 3000 students in each batch in each uni for the business degrees. HSG is a target in Switzerland but I am unsure about the prospects of getting a job in Switzerland or Europe given my non-eu status.

HSG is a 3 year programme with "guaranteed" exchange programmes while SMU and NUS are 4 year programmes and getting an exchange is a lot harder and almost impossible to get an exchange at a good university overseas. 
 

HSG seems like a much relaxed environment compared to NUS or SMU and it would be a lot more fun to spend my youth in Switzerland than in singapore. NUS quant finance is a very hard course and my friend who is already doing computer science in NUS says the life would be depressing and the competition would be international Chinese students who are extremely good at math. SMU is a more relaxed environment.

Cost-wise all three options are the same cost to finish the degree (living and tuition fees inclusive)

What would you choose if you were in my situation? I am inclined to going to HSG as I want to experience a new environment and learn a new language. But if going to the local universities gives me a much bigger advantage I would change my decision.