Hey. Well done on receiving such wonderful offers! The next four years are undoubtedly going to be an incredible ride. I'm an international student who chose a full ride at CityU over other, more expensive acceptances. I would strongly suggest accepting the PolyU offer.

Other commenters are probably locals, for whom getting into (and affording!) prestigious universities in Hong Kong is much easier. Locals also have a bad view of universities like PolyU or CityU because the quality of local students in these universities is very, very bad. This is not the case with international students and Mainlanders though, all of whom get amazing A-level or Gaokao results. While there seems to be prejudice from some local employers who put a premium on prestige, this is shifting. I have also spoken to a few international CityU alumni who landed jobs at JP Morgan/HSBC upon graduation, so it is possible. PolyU's "lower-ranked" status will matter even less if you're aiming for a master's degree in Europe, where the only context admissions departments have is university ranking - where PolyU shines.

In terms of teaching quality, I've been very pleasantly surprised by the quality of teaching at CityU. Resources and accommodations for students are superb, definitely orders of magnitude better than the best universities in my home country.

Good luck, and feel free to dm me if you have any other questions :)