I agree NYU is a great place to sudy a phd in economics. It's amazing how it has improved in the last years. However, I don't agree that NYU is better than NW or UPENN. First, we are taking about which school gives you more tools to become a sucessfull researcher, not about which city is better. And even when 5 years are a lot of time and it's important to be in a nice place, it's a secondary topic (five years of sacrifice in exchange of glory..I think it is worthy). Second, even when NYU has improved a lot, NW and PENN have been in the top ten for a long time. Even now, people argue if NYU is a to ten university or not, and I can assure you this doesn't happen with NW or UPENN.
NYU can be better in some fields, but taking the program as a whole, NW and UPEEN are, even at this moment, better.