actually here is my opinion on OSIP.
To me, OSIP is like to go there and have fun. Let's be realistic, if let say you've done well during your osip, that overseas company like you a lot, expressed interests to hire you next time when you graduate, would you go? afterall it's overseas, can you bear to live your friends, relatives, family in singapore? well, for me i can't.
If let say u are attach to a company that is relevant to what you study or something like that in singapore, gives you a good intern pay, likes you a lot, expressed interests to hire you, right after you graduate you already got a job waiting for you, so why not?
Going OSIP is just for experience only. For example, I am taking Chemical engineering, knowing that we are just diploma level, what sort of research can you do? as my school is offering some OSIP slots in universities and some research companies, no pay, your major project is just researching, what u going to do for the next 4 mths there is to do, research work.
What I am trying to say is, haven't you got enough of research work during your first 2 years doing projects and stuff? right? The purpose of internship programme is to let you learn technical skills that you don't learn in school, so that you are able to get use to the industries here and not learn skills like research work, afterall, at diploma level, what sort of research work can one do? wash test tube? goggle for documents to help your phd supervisor?