Things went pretty smooth except for the dependencies management of the importer. Because there is a lot of importers in the same gems, all dependencies are not mandatory and you have to install each of them manually to use your importer (ex. sequel & mysql gems for the Wordpress importer).
I opened an issue and got an answer pretty quick by the maintainer. A dicussion about suggested solutions is already going on, which is great!
In the meantime, enjoy reading my PHP and XHTML papers (your know, CakePHP was pretty cool back then).