Most Fairmonts treat me very well when I'm on a promotional rate. The exception is the one in New York - at the front desk, they got kind of nasty when I wanted to upgrade my corporate rate, which was lower than any other published rate. I spoke to the manager, asked him if he still wanted our business, and he grudgingly gave me an upgrade to a room that was barely passable by Fairmont standards (which leads me to believe that the "regular" rooms in this hotel must be pretty small). I now avoid that Fairmont, but not the others.

Hiltons and Starwoods both provide small upgrades, breakfasts, etc. even when on prepaid (i.e., Priceline, Expedia), promotional, or corporate rates. I'm Gold in both programs and have never gotten a true two-room suite upgrade off of ANY rate, but I usually get a larger minisuite-type room or something on the executive level (if there is one). They do not seem to distinguish based on how close my rate is to the "rack" rate.

I've never stayed at a Marriott using anything other than a Marriott.com booking, so I don't know how they handle other rates. I typically don't find that my corp rates are lower at that chain, and I haven't gotten a PCLN/Expedia Marriott room before.