That's weird. Where do you live? I'm Vietnamese and last time I was home, Macbook(s) and iPad were quite popular at the airport and cafe. I'm from Da Nang.
I do see a fair number of iPhones around though. Maybe because comparable Android phones aren't significantly cheaper.
Is it very expensive?
Regarding the iPhone, Vietnamese are crazy for the iPhone 4. Rich kids want cool looking stuff, they don't care about the price.
Btw, Apple even have an online store for Vietnam: http://store.apple.com/vn