we have stayed at the park hyatt chicago several times over the years. we have also stayed at many other well known hotels when we go downtown (from the northern suburbs). this place is really elegant, and if you can afford it, you will not be disappointed. great service, by professionals, in an excellent facility. the pool is great, restaurant great, and rooms great.
my only complaint is the "pet friendly" policy. one guest actually had his dog at (thankfully not in) the pool, roaming the deck. i thought this was really bizarre for such a property. really bizarre.
if you can afford it, and avoid the animals, this place is top notch.