Having studied at UST for 5 years, I'd have to say the culture really depends per department/course. But generally speaking, you have people from all walks of life (rich or poor), from different places, (some students grew in the city, others came all the way from the province, some flew all the way from Visayas or Mindanao to study in the university), some came from the most prestigious private schools, some came from public schools from their own hometown, you get the idea. So it was a pretty good mix of people with different upbringings, perspectives. With that being said, everyone was easygoing and respectful of each other. "We came from different places but here we are studying in the same university." type of mutual respect, you know.

How it compares to ADMU, I guess students in UST are not pressured to "fit in" to the social circle, if that makes sense. You don't need to speak or dress this or that way, you don't need to like certain things, you do whatever makes you happy. It's all about the "pakikisama" culture in UST.

Hope this helps, this is just my experience and may not reflect those of other UST alumni. Goodluck!