My wife did marriott plat challange last Jan-Feb, but you need way more than 8 nights...I was able to give her a referral for joining the program, and we each earned an extra 2000 points for the first 5 stays. She did 21 days for business, and made Plat...she loved it because she got instant status when starting the challange. she got lounge access and the hotel also threw a Plat Party every Tues with cocktails and good food. We did a week during spring where we alternated nights and got 4 stays each earning megabonus cat 1-4 passes (2 each). I like the megabonus vs HH incentives of triple points or whatever they do. We are using those 4 nights for a free long weekend in tahoe....she got the ritz carlton card which is the same points program...it gives lots of points and good benefits, and she can still sign up for the marriott card and get more points (i think both cards give points for first spend). Hilton is easy to get points with multiple CC partners and AXON awards are the only thing that helps with the high point cost for redemption.

I would suggest finding the "dream redemption" for each chain in your favorite vacation spots and compare them....then decide.

PM me if you need a referral for Marriott...start a new account and we both get 2k extra for your first 5 stays