The question suggests its own answer (though I might word it "forseeable need" rather than "immediate need," given that such promos generally come around no more than annually.

At least there is only a 2,000 point minimum, which would net you 1,300 UA miles.

Recall that the DL 25% promo had a larger minimum. Wasn't it 40,000 points, netting 25K miles?

I use the NW 25% to "top off" relatives' accounts to reach an award level -- even if there are no immediate plans to redeem. Topping off another person's account can be done with any carrier, except AA and BA.

One beauty of DC points is their flexibility. You have a lot of options, and can prepare for contingencies that may be completely unknown at the time.

A lot of this flexibility is lost when transferring to a specific program.

To definitively answer the thread topic would require good insight into whether this promo is likely to become an annual event like the BA and NW promos, or at least a regular one like DL.

Your answer also depends on how your own flying is distributed among various carriers. If a vast majority of your accrued miles are on UA, and you see little likelihood of transferring points to a different carrier, then transferring now would make more sense than otherwise.

You have until 15 January 2004.