Open Source ETL: Apache NiFi vs Streamsets

Actually it is easier, you have a nice-looking live dashboard displaying a lot of statistics for every processor while your dataflow is running. Errors are cleanly presented as red numbers on the processor icon and you can see individual errors for every faulty record with a mouse click. You may even put record filters on the connections between processors to inspect records in question. Filters can be applied while your dataflow is running, so I used it as live debugging tool.