Maintenace

I don't think such a database exists.

This won't give you information on specific apartments, but it will give you information on how buildings compare to similar buildings.

http://www.cnyc.com/

You're trying to compare apples with bananas with oranges. Maintenance varies widely from building to building, for a multitude of reasons. Doorman? Elevators? Live-in super? Underlying mortgage? Leaky pipes (therefore more water usage)? Is the board trying to offset deficit, or build up its reserves?

The comparisons they do have buildings grouped together by size, location and ammenities. It's not perfect (what is), but it does give you some idea of how your maintenance compares to other buildings that have around 150 units on the UES and so on.