We are Diamond with Hhonors and Platinum with SPG.
I like the fact that Hhonors has inexpensive partners in almost every city and town in the US, and some of the new Hampton Inns are really quite nice. I have commented to
Hunki that, if I could get a proper glass and tea cup at some of the new fancy Hamptons, I would think I was in a real hotel.

I also like the Hhonors free breakfasts. I am a serious breakfast person.
Our strategy is to earn points at reasonably priced hotels and spend them at really, really expensive ones. We attended a conference in Europe this winter where the rooms at the Hilton were over $700 a night. GULP! That was the time to use points. We have also had occasions where we took the kids on a trip and paid for our room and used points for their room.
On the other hand, we really like the SPG 4:00 p.m. check out and will make a point of booking a *wood property for our last day if we have a later flight. Hhonors properties are getting better about late check-outs, but they used to be nasty about it, even for Diamonds.
We just love getting the really fancy upgrades and will really miss that when we retire and lose our status.