Assuming running a dual hose inverter portable AC isn't against the lease agreement it would probably pay for itself based on the power usage. Pretty neat hack regardless.
Why? A dual-hose portable is more efficient than a single-hose, but a PTAC should (in theory) be more efficient (and possibly quieter) on account of having the heat-emitting side of the cooling loop outside of the living space, which is closer to the ideal split system - though I suppose that advantage could be undermined by the unit's age and condition.
Single-hose is always awful. It can't be other-than-awful.
All of the air that gets pushed out of that singular exhaust hose gets replaced by hot (and often very humid) outside air -- the same stuff we're burning electricity to fight a war against. (It is my considered opinion that single-hose portable aircons should not exist, and I'd remove them from the Earth if I had the ability.)
Dual-hose units can work OK.
They have some advantages, too, like being portable (they can be placed in the space that most-needs cooling instead of the space where they're mounted hard into a wall), or being quiet[er].
I've never experienced a PTAC in an NYC apartment, but some of the ones I've used in hotel rooms have been monstrously-noisy. I would never want to live with one of the noisy ones.