My partner in crime has done a lot of warehousing/data migration work, both with perl and with Informatica. He's also been placed in a similar position, where Informatica was essentially mandated as the tool to use. His comments have always been that Informatica can't touch a decent perl program.

I've also worked on a few large migrations, and I know that te only way to get those to work right (and be fast enough) was to use perl - there are always a ton of exceptions, and handling these with an integrated tool is non-trivial.

If I were in your shoes I'd try to show that I can do the same job in less time, and with a system that is easier to maintain.

Michael