On first impression, it's a disappointing building. I'd imagined from the title of the thread that it'd be like one of his cube sculptures - and it is, in a way - but I'm not convinced that something that works at the sculpture scale will work at the skyscraper scale.
I particularly like the one towards the bottom of the page with the five cubes on the diagonal, but I think what makes the sculptures interesting - the poise, balance, harmony, etc. - gets lost when it is scaled up.
On the other issue, New York mightn't be a particularly beautiful city, and parts of it might indeed be pretty ugly, but to me that's a significant part of its charm. I lived there for a few months in early 2001 (yes, I know it's a very different city now from how it was then, for obvious reasons) and it took me a while to understand how a city with so many vacant lots and such a general air of shabbiness (I was just at the Brooklyn end of the Brooklyn Bridge) could be loved by so many people. But I think you hit the nail on the head, paul h- it's the life in the place. It's trite, perhaps, to state that a city is so much more than its physical fabric, but equally it's sometimes worth repeating.
Chicago, where I stayed for a week, also impressed me, but for different reasons- the town-ness of much of it (as opposed to city-ness), the greenery, the freshness, the historic areas. But the downtown area outside office hours was one of the most boring urban experiences I've had anywhere.