The rest of the iPad presentation editors
The free-with-Google-account Quickoffice's presentation editor is basic, really aimed at touching up existing presentations' text and object placement, not creating new slideshows. And forget about anything like Keynote's animation capabilities. However, it's the only app besides Keynote that supports AirPrint and PDF export.
ByteSquared's $7.99 Office2HD presentation editor is likewise basic, aimed at touchup work. But it works with cloud storage services.
DataViz's $16.99 Documents to Go Premium is less than basic when it comes to presentation editing, allowing just text touchup.
Picsel's $9.99 Smart Office 2 is unusable due to a very poor user interface and limited capabilities.