I have to agree with Beverly.
I am a Marriott addict (own 3 weeks of TS and stay in Marriotts all over the world, by choice), as well as a Manhattan Club owner, and I would choose the MC over the Marriott Marquis any day of the week - especially with 2 teens in tow. We have 3 grown children and you can't beat the savings and the convenience of the MC, especially at Christmas.
BEST TIME OF THE YEAR IN NYC!
There is nothing to compare with the convenience of having your own apartment for the privacy of 2 rooms with 2 full bathrooms and 2 TVs/VCRs etc. And if your teens are reluctant to share the queen size sofa bed, you can have a roll-a-way bed (sturdy with a good thick single bed mattress) free of charge.
Breakfast and an occasional lunch or supper in your apartment can be a big savings, not to mention convenient and comfy. If you are not into that, continental breakfast is available for $10 per person at the MC and the restaurant in the Park Central Hotel (same building) is convenient, as well as the classic diner style cafe (less expensive) across the street in the Wellington Hotel and a more upscale "European" experience at the Cafe Europa 2 blocks north towards Central Park. Associated (grocery store) is a block away and there are plenty of good delis, restaurants, liquor stores, bakeries and bagel shops within 2 or 3 blocks of the MC ....and oh, yes, an absolutely great seafood restaurant across the street. What more can I say? Location! If you want to be in Times Square, go there but don't stay there. It's a short subway ride away (subway stop, 1 block from MC ) or a brisk walk (when in midtown, I ONLY walk). And consider the cost of the Marquis or the amount of points you'll have to give up to accommodate 4 people in a room with 2 double beds and 1 bathroom (with 2 teenagers?? for a whole week??) in a hotel that is as busy as Grand Central Station and charges you an exorbitant price for every little extra. I've done both and the MC is the better choice, by far.