What are you doing, algo trading or data munging? I wouldn't exactly use it for stuff that operates on the scale of nanoseconds, but beyond that all you have to do is look at recent talks like, "Christopher Jack - Using Perl to parse terabytes of mission critical variable" from TPC in the Cloud over the summer. But I think it is certainly appropriate for a whole host of supporting uses, again just not so much for real time HFT bots.