some
condos do not have anything different from HDB in the sense that they do not have swimming pool nor gym - think it would be called private apartment?? (i am not sure bout this) however,
condos usually have those inhouse facilites such as cable tv and internet connection installed, where in HDB you have to install them by yourself. notice that your plan is sharing a place (not renting whole unit), suppose you can try get HDB where the owner had sorted those things out.
if you lived in HDB, you can feel the real singaporean living.. people chanting on hungry ghost festival, morning taichi, cheaper and exotic food, etc.. in condo, in other hand, will give you more opportunities to meet people (more likely expats) for clubbing pals!
fyi, i was livin in HDB, but now livin in condo.