I am gold, my stays are at least 4 nights each time and already passed 30 nights this year. Got the 2 free nights for 4 stays by 7/31 offer. Not great giving my patterns but will probably try to claim 1 night.

I did have the misfortune of picking the only non-participating hotel in a state last time round. For this, the T&C says "over 1,200 participating Starwood hotels and resorts" and "A listing of SPG-participating hotels and resorts and a description of eligible stays and eligible rates can be found at spg.com under the program terms and conditions." So, I guess all of them participate?

It looks like IHG has the best deal for me this time round (night based) - of course that is after not participating at all in the last 2 rounds with them. You got to play hard to get to get what you want