Having written in both Tcl and Perl, I think I prefer Tcl because code can remain readable. I have a really hard time going back and reading my old Perl code. Maybe that's just bad programming style on my part.
However, the fact that Perl has such a *HUGE* number of libraries to do every conceivable thing often makes me pick it over Tcl or Python. Is there a CPAN for Tcl? And what about an easy way to get loadable modules into the Tcl interpreter in AOLserver?