We ran similar performance tests, in this case between Pentaho (PDI ,also Java based) and SSIS. With SQL server SSIS is faster (about 10%), perhaps due to native OLE-DB connectivity. However, I very gladly lose some speed when developing ETL dataflows/transformations is so much quicker with PDI. Pentaho offers more functionality, especially for non-relational db sources. It is very stable without the SSIS glitches, with a limited set of internal datatypes (instead of the annoying number in SSIS) and parsing is immensely superior.