What is the difference between Acceleo and Xpand?

Question

I have a DSL which is based on a custom metamodel, which in its turn is based on EMF/Ecore. I am trying to figure out which solution to choose, and I cant find any decent comparisons anywhere.

Does anyone have any reasons why I should choose one over the other?

What I know so far is that Acceleo uses a OMG standardized language, but it seems harder to use than Xpand.