NYU undergrad is very very hard to get in. here are some statistics of the website
Student Profiles
? Number of applications 33,097
? From top 10% of HS class 70.50%
? Middle 50% of freshman SAT 1300 - 1450
? Early decision acceptance 32.90%
? From metro New York 37.80%
Now those attending NYU undergrad will tell you that it is very demanding to major in sciences at NYU. And it's also very expensive. I agree Columbia is a bit more selective but it's and Ivy League school with different selection criteria.
as UBTom mentioned the NYU dental class is rather large and that's why I think it is a little less competative. I don't have that much info on the Dental school, but I know that I see them sometimes, in large white van that has dental students offering services. I hope this helps, if you need infor on Undergrad NYU PM me.