My now retired husband worked for IHG, Starwood and Marriott. IGH always had the best rates and they used to be a standard rate across the board ($29, $49, $79, etc). Starwood was next as far as great EE rates. Marriott was the least generous, but if we were flexible (and we generally were) we could score some good discounts.

The other issue with Bonvoy is you can't always make reservations very far out. It used to be up to a year, but we found that the window was down to about 60-90 days in advance.

Hope this helps.