Columbia University obviously has a great academic reputation and consistenly makes US News and World Report's Top 20 national university's list. There are a lot of great thing about the university, some that are amazing and some that are amazing depending on your perpsective.
One thing to be aware of is that Columbia is heavily tilted towards graduate students with a 2 to 1 grad to undergrad ratio. This is something to keep in mind and does end up affecting the feel on campus.
Also, Columbia is obviously located in New York City. For some, especially those from far away, this can be seen as a boon and Columbia definitely positions itself in that light. You have all of New York City at your fingertips including all the cultural attractions, tons of amazing historic sites, and great restaurants.
However, being in the "middle" of Manhattan also detracts from the college experience. When you are on the Columbia campus, you don't feel like you are in the middle of the city, my impression was that student life is less compact and student centered than at other schools. Friends have coraborrated this and say that student life isn't campus-centered.
There are tons of advantages to attending Columbia, but it's presence in New York and student makeup can' also take away and are things to consider.