We stayed during three nights at park Hyatt. And it was great experiences too see Shanghai like this. Even if we are quite familiar with this city, we rediscover completely Shanghai from the top of it.
The service was really professional, all what you can except in this kind of place.
Our room was apparently the smallest one but still quite big and really comfortable.
We took a room with a view on the bund, which, I definitely recommend even if it's a bit pricey.
We enjoy the swimming pool (it look smaller in real than the picture from the website), and the gym area was really nice too. The breakfast was also great a lot of choice.
We try to eat at the 100 century avenue restaurant, but It was too busy and noisy so finally we ate two times at the Living room which is much more cozy, the food was not spectacular but the view is!
If you don't know Shanghai well, the location might be a problem because it seems far from the others Shanghai attraction. But this can be resolved easily by taxi.
It was really great and relaxing to be in this kind of environment during three days.