My sample size is one, but I have a high school friend who went to a top school for college and is now at another one for graduate work
From my more humble vantage point it's been incredibly damaging. He has no social life outside of his career ( basically the people living the same lifestyle) and has been molded to be single mindedly focused on his studies. He's honestly in most ways has because a more dull individual.
(This is kinda funny b/c they were sorta conceived to emulate Oxford and Cambridge - which as I understand are all about he well-rounded "liberal arts eduction")
However that being said, it's hard to argue with the fact that all his colleagues and all the people he meets are incredibly intelligent/hard-working and he in effect has access to the best minds in the world. The fact he is so "networked" mean ofcourse he will always have a very well paying job, and most likely will eventually be in a position of power.
EDIT:
A corollary would be that if young Jack Ma went to Harvard, he wouldn't have become current Jack Ma, and would probably be another wealthy lawyer or something