Different chains give differing points for each stay and charge differing amounts for their rooms, so it probably works out even.
But for those of us who amass most of our points from charge cards, there is no questions that Starwood is the way to go. It requires many fewer Starpoints for a room than any other chain.
Last summer, we spent 5 nights at the Ritz in Maui for 150,000 Marriott points, but 5 nights at the Princeville in Kaui was only 48,000. I could have stayed 15 nights for the same amount!