Both have thie pros and cons
Hyatt Regency:
pros:
1. Nearest Hotel to the Airport
2. Good for shorter stay (for 2-3 days)
cons:
1. Noisy due to airport flight blares
Grand Hyatt:
pros:
1. Good for longer stays (like for a week or so)
2. Excellent accomodation facilities & locality
cons:
1. Distant to the Airport
My Clients from US stayed in Grand Hyatt last time .....
I am not sure abt their fares
though