I think it's impossible to predict devaluation and the availability of low-level award this far out, but as always you can improve your chances by being really flexible on your travel dates.

Ordinarily I would say hold off on transferring points until you are ready to redeem them for award travel, but some believe the tremendous AmEX MR transfer bonuses are incentives meant to rope in flyers before the United/Continental programs and cards get merged, and therefore may not last. I think we've seen the 40% bonus before, however, but 25% or 30% bonuses have been more common.

If this is your first time transferring MR points, you're eligible for an even better deal before September 30. If you need MQMs at all, jump on this:

http://dmn.delta.com/ace_offers/junemr/