How about 4x miles?
If I fulfill the 25 night requirement for the current points promotion early enough, I may try switching over to miles and enrolling in this one if they'll let me.
I completed my nights stayed requirement for the summer bonus promo and was able to succesfully enroll in the 4x miles promotion. I called customer service first just to make sure it wouldn't disqualify me from the points promo and they said there should be no problem.
If anyone else is thinking of doing this, I'd wait until you see the bonus points actually deposited into your account (probably 2-3 days after your stay) before switching just to be on the safe side.
Also, remember to update your profile for miles and enter your FF number PRIOR to registering for the promo.