I used to do all these promos in my pre-TS days and they are quite good for racking up free stays.
I don't follow them as much anymore since I almost exclusively use timeshares, but
it's getting tougher to always get what you want with timeshares so still find I need
those hotels, especially for city stays and Europe.

http://www.frequentflier.com/blog/fo...0-bonus-miles/

If you’re not already a member of Marriott’s Rewards program, the upcoming MegaMiles promotion may be a compelling reason to sign up.

Offer Details

Between February 1 and April 30, new Marriott Rewards members can earn 5,000 bonus miles after every second paid stay, up to a total of 50,000 bonus miles.

New Marriott Rewards members must enroll and register for the promotion by March 31.

The MegaMiles offer cannot be combined with the MegaBonus offer (a free night after two stays during the same period) because the latter requires that the traveler opt to earn points rather than miles.

Deal or No Deal

For Rewards members choosing to earn miles, the normal earning rate depends on the airline program, the Marriott brand, and the type of charge. Delta SkyMiles members, for example, earn two miles per $1 spent on all qualifying charges at JW Marriott, Autograph Collection, Renaissance, Marriott, and Marriott Vacation Club; two miles per $1 spent on room rate only at Ritz-Carlton and EDITION hotels; and one mile per $1 spent on room rate only at Courtyard, AC Hotels, Fairfield Inn & Suites, SpringHill Suites, Residence Inn, TownePlace Suites, and Marriott Executive Apartments.

So two $250 one-night stays at a Marriott would earn 1,000 Delta miles. In that scenario, the 5,000 bonus miles would amount to a tremendous multiplier.

Promotion pros

Solid bonus, especially for cheaper stays
Miles available in more than 30 airline programs
Promotion cons

Current Rewards members are ineligible
For mileage collectors, this is the best of the winter hotel promotions.