Like the idea. Think you need to figure out a way to get people who are happy to submit data. Like Glassdoor, I'd guess that the unhappy are more likely to provide data. Especially true for folks in the city who feel they have a great deal - why would I advertise that and tell others about that?

Beyond that, didn't like the fact that I provided data and got a "no data available" page. I understand your building up the dbase, but it didn't leave me with a great feeling (not a biggie). Perhaps you could show me some data for close by areas so at least as a user, I feel like I benefited somewhat.

On amenities, would add -- Doorman building

At some point, you could perhaps mash up data you get about buildings with a lot of the data NYC has opened up about the city as part of its gov2.0 efforts. This way, you can provide a sense for the "value" of an apartment alongside stats like average income of neighborhood, crime rates, etc.

But of course, building up your dbase is priority one. Good luck.