What exactly is it regarding perl's automation that you aren't comfortable with? I haven't used Mechanize, but I'm sure a well designed script would be reasonably robust.

I don't know about the original poster's issues, but javascript-heavy sites don't work well with WWW::Mechanize. Particularly annoying are webapps that use javascript to generate the HTML you see in the browser, because Mech won't let you submit form fields that it doesn't think exist.