The problem Spruce has is that it is closer to downtown and thus crowded out more. I agree with 56 Leonard because it is a fascinating tower and in a location where it gets plenty of attention.
I also think 432 Park is iconic. You can see it from like everywhere and in a short time has already become something associated with NYC. It is a box yes. But it is a very skinny 1400 foot box with perfect symmetry.