When I had to choose I preferred the look and feel of Win32::GUI but the documentation concerns raised in the other posts are valid. This is not to detract from Aldo's work. A Perl wrapper for the win32 API is a Herculean task to undertake.
On a related note: over a year ago I wrote a Perl program to convert Delphi/C++Builder Forms to Win32::GUI templates. This allows you to use Delphi or C++Builder to design Win32::GUI clients.
I am not upgrading or maintaining this anymore but if anyone is interested in using it or extending it they can find it
. It could probably be modified to support TK so that there was Yet Another Client Designer. ;-)