Does XPP still exist? I thought it is dead for quite some time now. I remember that SDL had bought XyEnterprise in 2009 and somehow merged it into their CMS. However, SDL heavily slashed down all their non-translation activities earlier this year. Not sure, if going this solution is a good idea as it does not seem to have a future … But this is just my personal thought!
FrameMaker is an excellent tool for XML publishing. Especially combined with Adobe's new DITA CCMS ("XML Documentation Add-on for Adobe Experience Manager") you have more or less endless possibilities for on and offline-authoring, managing, reviewing, translating, publishing, analyzing. And you can publish XML Content to pretty much all channels from high-quality PDFs to Websites, dedicated Responsive HTML5 sites, ePUBs, Kindle e-books, iOS / Android Apps, Adobe DPS and much more. And all this very easy with visual tools and no need for expensive and time-consuming programming.