Folks confuse this with the Lipstick Building because it's round and in the same neighborhood.

The Rube likes it most for being so blue. Like other metallic buildings, the apparent color can vary greatly according to the lighting conditions, and in the current instance, by the degree of saturation applied by the photographer in PhotoShop.

Not everyone likes it, though; here's Susan Sirefman from her New York: A Guide to Recent Architecture:

"Helmut Jahn is one of this decade's most prolific architects -- perhaps too prolific. Certainly 750 Lexington Avenue is the antithesis of reflective elegance: unwieldy, crude and awkward, it is proof that quality should come before quantity.

A series of geometric volumes, the building consists essentially of a rectangular base interlocked with an octagon that props up a series of graduated cylinders. These cylinders start out large and end up quite small with a floating ball balanced on top, producing an effect not unlike that of an elaborate cake. The composition is as static as any 31-story skyscraper could be, with blue mirrored cladding that denies it any hope of grace."

This 3rd Avenue view of it will be obstructed soon by a new Cesar Pelli skyscraper, currently under construction.