I've been using http://brunch.io and enjoying it. Far less configuration than Webpack.
I have a few github issues open that haven't been touched in months!
I used brunch with a rails app. Breakfast gem. Not as fun to use as it seems, since doing anything out of the norm is almost impossible to find documentation on.
Honestly, Webpack was easier to use, simply because it is easier to find information on the web about it.