Interesting discussion.

I don't think promotions change my behavior unless one chain has a significantly better promotion. I basically look for Starwood and Hyatt. In Minneapolis, for instance, the Hyatt is a bit of a dump so I tend to go for Starwood. I particularly like the Westin and W. So, Hyatt would have to have a much better promotion to sway me (buy 2 nights, get one free at Hyatt versus a lackluster Hyatt promotion would do the trick).

So, assuming no promotions, I guess the property itself would be the deciding factor. I would only be swayed if one chain had a MUCH better promotion.