Your answers will be affected by the elite status of the responders. When you have elite status, you call a dedicated line and tend to get better service.

That said, they all have pros and cons. I know nothing about Priority. Starwood is great as I like the ability to transfer to airlines and to get great rates on hotels with Cash and Points. Hyatt treats its high-level elites very, very well - free breakfasts at Park Hyatts are a very, very valuable perk. Hilton treats mid-level elites very well. Marriott has never impressed me and the award levels are high for what I receive.

Hope that helps.