You have touched upon a very controversial subject! I have worked with many people who will only live in one or the other. It is simply a matter of preference. A lot of people love the character of older/pre-war buildings. They typically have beautiful real-wood floors, high ceilings, gigantic windows, great closet space, and charm. However, newer buildings definitely have their own set of alluring features. They typically offer more amenities than the pre-war counter parts. Some newer buildings, such as the Atelier on 42nd Street, offer insane amenities such as a gym, screening room, roof deck, tennis courts, playgrounds, volleyball courts, driving range, and more! The list goes on and on. The newer buildings also typically (although not always) more environmentally conscious. For example, the Helena on 57th Street has its own wastewater treatment plant, as well as a "vacation switch" for the entire apartment that essentially helps your apartment hibernate while you're gone.
All in all, it comes down to what you're looking for. Whether you love the character and soul found in pre-war buildings, or the luxurious lobbies and amenities of some of the newer buildings, the perfect home is out there for you.
Please feel free to contact me directly if you have any other questions, or would like to discuss this one in more detail!
Licensed Real Estate Salesperson
114 Perry Street
New York, NY 10014