Open source ETL vs commercial ETL

Anybody have experience with open source etl like Talend or Pentaho? They are becoming more popular, and I was wondering what advantages/ disadvantages of open source vs commercial etl tools. Any downsides of using open source for SOX or HIPAA?

I don't see how open source or not has any bearing on SOX or HIPAA. (I mean, so called 'SOX compliant' organizations do a lot of reporting from spreadsheets...).

Open source is usually less expensive, but one thing to understand is that ETL tools, on the whole, is a small market and the talent pool of knowlegedable developers is even smaller (relative to other application development skill sets). So even if you find an open source tool that will do the job that you need, you will probably be faced with having to train people to use it and burn a lot of time reworking processes as you become more skilled with the tool.

I'm also curious about peoples experience with TalenD or Pentaho? We are looking into providing a SaaS environment, would TalenD be a good candidate? I ask because of the lack of API to manipulate the definition of the jobs before they are run.

Thanks,
Jonathan