My situation: early AM flight out of Philly, spending the night in New York City, five people. Thus, optimal way to get to Philly at odd-hours is a one-way rental car for $150 or so. Probably leaving Manhattan at 4AM.

Ordinarily, I'd rent a car the evening before, drive it to the hotel, pay $50 to park it, and leave from there at 4AM. I'd probably make a backup reservation at another agency in case Hertz didn't have a large car, SUV, van, etc.

However, I see Hertz has these 24/7 locations all around Manhattan. Are they reliable? Can I expect to walk up to one with a 3:30AM reservation and seamlessly/quickly pick up a car? Or - better yet - could I walk up to one with an 8PM reservation (early enough to run to my backup if the kiosk isn't working or the car isn't there), get my keys, and then leave the car where it sits until 3:30AM before driving away?

Guess I'm just looking for thoughts on the reliability of the 24/7 concept, knowing that this is a rental where I can't afford to have issues or delays of any kind.

Specific location is Doubletree Suites Times Square, if it matters.