Alan
The difference is is how data is processed
Visual Importer ETL is using import script which works very well when you do not need complex transformations
www.etl-tools.com/wiki/vimpe:importing_data
Advanced ETL Processor is using data-flow/mapping designer
www.etl-tools.com/wiki/aetle:processing_data:screen_overview
That allows to perform very complex transformations which do not exist in Visual Importer ETL
Joining Data
Sorting
Grouping
Valuation
De duplication
and much more
The rest is the same.
Repository structure is the same
I hope this information is useful for you
