I'm not sure why this is being marketed as "professional" 3D modelling.  I don't know many professionals doing production work on a smartphone.  I see this as great tool for mockups and prototyping, which could be transferred to a workstation for refinement.  Working seriously on a screen less than 17 inches is not what I'd consider professional, but professionals could use this tool as a way to flesh out designs or concepts on the go.  For this reason, I would hope that the full version supports a robust list of export formats.  Obj is ok, if the format's internal options are exposed in the export dialogue, but ideally I would like to see fbx and Collada.