Fonts and interface chrome always seem to take up a tiny bit more space on OS X. Not usually an issue but I'd take it into account if, on Windows, a given res is barely usable.

I have a 13-inch air; the pixels are tiny. If you try 1440x900 on a large monitor, bear in mind smaller fonts may not be using once you shrink down to laptop size.

Apple stores seem pretty liberal about machine use (notwithstanding the guy being prosecuted for installing webcam upload software on a store's machines..) - maybe you could download Mac Eclipse to a USB key and try it out on a machine?