Off the top of my head I can't recall any real security issues. In fact, I gutted the bastard and put in my own security, which was secure :) So, I don't recall if I found any.

And yes, I am talking a large site with a few million hits/day handling a few hundred thousand Db queries per hour. I think whenever I fixed what was wrong with the caching, it sped up. I wish I could remember the details, but I seem to have blocked it from my memory.
Still, try Mason or something that you could actually reuse for a larger app later on.. since using ePerl would be silly.

Cheers,
KM