I've been playing with WxPerl for the better part of today and I must say it's really really good. In fact, it's the first Perl GUI toolkit that I feel good using. Tk works fine, but it's ugly and I keep getting lost in the docs. WxPerl looks native and Wx (the C++ foundation) has very good docs and is well mapped into Perl. Of the other GUI kits Win32 is a pain to use because the underlying system is a pain (not to mention that it's not portable, and I use Linux most of the time) and the others I tested (Gtk, Qt) simply don't build anywhere I tried.
What I'm trying to build is a small but complete app (a use Perl journal editor) in order to get a good feel for WxPerl as I intend to build a complex app soon after that. So far things are looking great. I'm taking my time as I test every other little option to see what it looks like (and am trying to do it cleanly because I know GUI apps become huge messes before you know it), but overall coding is fast.
Of course, I couldn't just sit there and do GUI programming without throwing in a little...... -- surpise ! --