All statistics packages have their strengths and weaknesses so it is not uncommon for people to want to use more than one – even on the same project. SOFA is focused on making it easy to use some core statistical tests and producing attractive, high definition tabular and charting output. SOFA also makes it easy to link to, or import from, a wide range of formats: xls, xlsx, csv, google docs spreadsheets, MS Access, NySQL, MS SQL Server, PostgreSQL, SQLite, and, more recently, CUBRID.
But there is no point overcomplicating SOFA so it can do every statistical test that might be needed for a particular project. SOFA users have been routinely surveyed on what features they would like added and it has not consolidated into a clear list of priorities. People need lots of different things depending on their specific projects.
So a sensible goal for SOFA is to make it easy to import and export data, including metadata such as variable and value labels. This strategy has already resulted in the addition to SOFA (version 1.4.2) of built-in export-to-spreadsheet functionality. And it has already been improved for version 1.4.3 (not released yet at the time of this writing).
The question is, what packages should SOFA target as priorities for interoperability? Feel free to fire me off an email at firstname.lastname@example.org.