Let's see...
IA: Die die must get into the company that you want to be in, if not you'll be wasting time. Anyway, not all good companies hire their previous interns, it depends on how much money the company spent on training you.
Another bad thing: 10 AUs earned just for the whole semester is very stupid, when normal load is 18AU. And you still need to pay school fees. So get a company that pays you ridiculously well, like $1000, if not really waste time.
IO: More often than not, you must find yourself, though NTU has its own IO system as well, and alot of gahmen agencies take in interns through this system instead of direct.
Plus it's done during summer hols. Means you get to earn extra money during tt time.
Only thing is that you must tambah 6 more AUs of electives, but that isn't a problem if you take biz minor.
For me, I've switched to IO after failure to secure my 1st local and overseas interviewing companies. But I was in a special situation for the overseas company (damn big one sigh) last minute withdrew from IA due to the 2008 economic crisis, thus I was allowed to change.