They are both grammatical. We tend to put better in the first position with short complements and the second position with long complements, so English speakers would tend not to use the starred sentences in the pairs below.
*With his new, expensive shoes, he's better able to run.
With his new, expensive shoes, he's able to run better.
With the reorganization, we are better able to respond to climate change and pursue sustainable development.
*With the reorganization, we are able to respond to climate change and pursue sustainable development better.
For your sentence, with an intermediate-length complement, both positions sound fine to me.