If you tune to the Marriott section of this site you'll see a lot of peoples' pros and cons of Marriott's points versus Hilton.
The conclusion some of us seem to have arrived at is that Hilton probably has the best program for mid-intensity travellers but that Marriott is better at the platinum level.
Personally I still think Hilton is best. Anyone care to comment?
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AC SE
BA Gold
This has been my experience. I travel enough to make Diamond, and enjoy the way I'm treated at most Hilton properties. I don't travel enough to hit top tier Marriott however which means I was always in the middle of the pack and getting a parking lot facing room at Courtyards.