I own and operate a quantitative finance business. Pandas (+ numpy) has been a godsend. Not only do I not have to pay for matlab licenses, but even the less experience programmers on my team have been insanely productive.
not the person you're responding to, however I also made the change in the financial industry for a variety of reasons.
but the main one for me, was that python does non-math things much better than matlab. Since python is a general purpose language you can go from analysis to production application much faster, whereas with matlab it usually involved getting a software developer to rewrite it in java.
We used to take our python analysis code, wrap it up in a web app, and then use that to server risk information to traders, and it was quite easy to do so.