Not having used Tk I can't comment on that side but after much fiddling with Win32::GUI I have written a few scripts using it. I liked it. The lack of documentation was part of the fun (although it has got substantially fuller since I started using GUI).

I found that quick setting up and building of simple(ish) windows was pretty quick with Win32::GUI - even for a relatively new Perl programmer (9mths) so I wouldn't hesitate to recommend it for simple tasks.

Since everyone is raving about Tk I'm going to have to take a look!
c-ya.

Larry