I did not vote, since I am not certain whether V/M or D/W will win the GPF. As FSGMT mentioned, typically V/M peak later, while D/W peak earlier. History would seem to favour D/W. However, many people (including several Figure Skating celebrities) think V/M have a very strong FD, if they can iron-out the technical kinks.
D/W debuted their routines at SA in October, then had about 6 weeks until NHK to tweak the routines based on the feedback received from the judges. V/M also debut their routines in October at SC, then had 2 weeks to tweak the routines before skating again at COR. Afterwards, the situation reversed. D/W have had 2 weeks since NHK to further tweak their routines, while V/M have been working on theirs for the past 4 weeks. However V/M may have a disadvantage, since they have not received any recent competition feedback about the tweaks they have been making over the past month. The GPF will be their feedback for Canadians, 4CC, and Worlds.
I am sure Tessa and Scott would like to win the GPF, since it is the one competition they have never won. However I suspect if they had to choose between GPF and Worlds, they would likely prefer to win Worlds because it is in their home town/country. If Tessa and Scott are planning to retire after Sochi, Worlds in London may be their last chance to experience some of what they felt after winning Gold in Vancouver.