Does anyone think that "cheap" concrete could support a building 1,397 feet tall and only 93.5 feet wide? That's a 15:1 height:width ratio. So obviously the concrete is high-strength, and expensive.
Visually, we can see quite a difference between the architectural concrete and the concrete at the retail level. But they are both expensive, high-strength mixes. They're not just pouring cinder block-type concrete for this building.
We have relatively few photos of direct sun striking the architectural concrete (due to the modest height of the building so far), but in those we do have, that concrete looks excellent. And the upper levels of the building will be exposed to more sunlight as the structure ascends above the surrounding buildings. This building will be tremendously bright on sunny days, and will have very different appearance depending on the ambient light.
I think the design will result in an iconic an impressive skyscraper. The only concern I have is the windows. Not the glass itself, but how is it set in the openings. Visually, it would be better to eliminate the black surrounding area for visual appeal. Also, if they leave a gap between the windows and the concrete as we see in the closeup below, pigeons and other birds will definitely try to roost there.
Overall, the symmetry, proportions and bright concrete should make for an impressive structure. It will be interesting to see how 432 Park will complement the other giant towers that should be standing near it ten years from now: One57, 225 W 57th, 107 W 57th, Torre Verre, and 1 Vanderbilt.