Based on how the competition has gone, I don't think Amy & Maya can possibly win. I feel like they will get a huge early lead but they will get lost like Jeremy & Sandy, and probably finish third. My opinion on this will only change if they manage to snag a first place before the finale.
I voted for Misti & Jim because they seem like they went through their development arc like Tammy & Victor. However, they might get to the final Roadblock first and then one of them will royally mess up, Misti (as was foreshadowed early in the series), or Jim (as karma for the cockiness).
Adam & Bethany could win, but the competition vs. the dentists will be fierce, they might be susceptible to be stumped by a detail-oriented task, probably the memory challenge if there is one.