I plan to get Both, so whichever one comes first. Though I am not sure if Ferb is going to be a figure or not, as we have Phineas, and Agent P confirmed, but not Ferb or Candice or any of the others. Lots to choose from in this category, so my guess is that Phineas, and Perry will be a Toybox set, but not a full playset.
Either one is going to be a great choice.