I'm curious but if you don't mind me asking, was it because of the funding?
I'm in a situation right now (different program) where I really like this school, research, students but it's a partially funded program with no future guarantees.
Holding out for 1 fully funded waitlist offer.
I interviewed as well and having it so early on it rose to my top choices. However after interviewing at other replaces I got the same impression as you.
Still a great program but 2 things stood out:
1) They don't really have traditional labs and instead utilize large datasets
2) Not much opportunity to publish with faculty. I asked a couple of 3rd-4th years who planned to go into academics and they were just prepping for their first pub