Have links to the models?
Battery life: How the laptop is used - how heavily it's tasked - has a lot to do with how long a battery will last. How will you use the laptop?
Have you found any independent reviews on each of those models?
I guess you didn't find any reviews on the 12" model. What reviews did you find on the 11" model?
Click on the models in the first line for links. Here's a review on the 11.6"
. For the 12.5" there's this short review,
which says nothing about the battery.