Mark and Tracy (and Bay) -to put it briefly- are the kinds of hosts that go above and beyond, really, and that's not to mention the apartment already has every single thing you could think to need, all on top of the fact the space is one of the coolest designed places I've had the pleasure to stay in!
Highly recommended! (it's hardly a minute or two walk from the subway -- 15-20min to midtown, right next to Morningside Park, and quick 5-10 mins from Columbia University)