Once hitting Plat last year, I thought about switching to another chain to get status in that program too; I'm already SPG Gold due to my AmEx and thought about switching to them or Hyatt/Hilton/IHG. I've been working away from home 4 nights/week since Feb '09 (and will be for the forseeable future ), so I'd eventually make top-tier in any program I'd join.

... then I did the math. Since I pay out-of-pocket, it's 90% about value for me, and I might as well get something out of it other than a bed every night (which rules out going to the cheapest non-chain hotel I can find, and last-year's Marriott stays are paying the hotel bill for my Ren Vendome Paris stay this fall).

Not only did Marriott properties have the cheapest prices in the two "away" locations I've been staying this last year, IMO I'll have better opportunities to use my Plat status and/or points with a Marriott property, so I have a compelling reason to retain my loyalty in MR.

For example, I got a targeted(?) offer from Hyatt (or Hilton, I forget) for 50K points if I stay 4 nights before 4/30, IIRC. I almost thought about it, then I realized that I haven't stayed in [whichever chain that was] in years, wouldn't switch after the promo was over to take advantage of the points bump at the prices they charge, and I still wouldn't be even lowest-tier status, so I'd pay $240 more for that week for points I really wouldn't use.

Of course, were I traveling on OPM, I'd have top-tier in every program that had a bed for sale by now