For me the biggest factor will be how they treat Lifetime levels.

I'm Lifetime Gold w/ SPG and if Marriott downgrades me to Silver (or some new category with far less benefits) I'll be very unhappy.

Also, I'd want a fair credit towards Lifetime Plat. Unfortunately, I don't have the years in SPG (just 6), so I'd rather not have my progress be devalued.

THat said, I don't think any of the other programs are amazing anymore. If I leave Marriott, I'll just start doing the same thing I've switched to with airlines....Stay where I want, when I want and pay whatever it takes for the room I want without regards to loyalty.