My family stayed there in Dec 2006. We bid $45 on priceline and I was thrilled to learn that I would be taking my family to the Hyatt Regency. Beware, however, as parking is $15 per night and the shuttle does stop at least 3 other places nearby before taking you to the park. After parking fees and taxes, my $45 "deal" ended up costing roughly $73/night. I will definitely stay across the street next time for $60-$65 to get free parking, super-close location, and a free breakfast.
The hotel itself is very nice and clean, everything one would expect from Hyatt. My kids were 3 and 2 at the time and I didn't think the Hyatt was very kid-friendly in terms of the type of furniture in the rooms. I was always having to be on guard to make sure my kids didn't trip and knock their heads against the steel and granite cocktail table. The hotel is great for adults and anyone traveling on business, or even families with older children who can resist jumping and running around in the hotel. For young families, I recommend something closer and cheaper.