Great location, okay service, expensive!
The Hyatt is a very nice hotel, with clean rooms and a great view of downtown Vancouver. The room had a simple, elegant, Japanese style to it, which I found very pleasing and comfortable.
The hotel is right in the middle of downtown, which means that you're in the middle of great restaurants, shopping, public areas and museums. No need for a car, as most major sights of Vancouver are walkable, and the Sky Train station is just below the hotel. This location unfortunately also means a long ride from the airport. My taxi fare was $30 each way, and the hotel doesn't provide a shuttle bus.
The wireless internet connection was fine, but difficult to set up. I only had the option of signing up for one day at a time (for $10). There's no way to sign up for the duration of your stay. It also took two calls to the hotel's tech support to get the connection going in the first place.
I had some trouble with the service - my room was not clean when I opened the door, and I had to get the front desk to deal with it.
Meals at the hotel are quite expensive (breakfast will run you $35!), but the nearby restaurants help out there (try Cafe Crepe (about 2 blocks away on Robson) for breakfast or lunch - great crepes and full breakfasts! Also Rex, across Dunsmuir from the hotel is great for prime rib). The 24-hour fitness center is first-rate, with several treadmills, cycles and cross-trainers, four or five resistance machines and a good set of free weights. The pool just outside of the fitness center is quite nice.
I knocked a point off of value because it's an expensive hotel, but so is everything in Vancouver. They lost a couple of points on service because of the cleaning and internet issues. It's a very good and comfortable hotel if you can afford it, though.