Long time ago I have used pentaho and talend to build integration, I ported customer center to Drupal/Joomla CMS in 2009 and published the integration on the official user forum, guess what happened NS banned me from the forum. I worked along with Celigo( they used to be an implementation partner long ago). I think they use pentaho as their underlying platform for the connectors

We don’t use Pentaho at all (not that there’d be anything wrong with that I suppose).