I chose Tk because
#1 I was learning Perl and wanted to add a GUI to a program I was writting. What better way to use what I was learning and accomplish a task.

#2 Tk was easy to pick up. Granted the geometry managers took some study but everything else was a piece of cake. I particularly found the widgets interesting and there are soooo many more widgets available than the standard ones.

#3 Perl is fun so by default Tk is fun!

What I don't like about Tk is um um
#1 well I had some issues with the placement of the Dialogbox widget

#2 I have problems packaging my programs sometimes with pp or tkpp

All in all if you need an easy, fun, quick GUI solution Tk is the way to go.