I use the PerlApp from Activestate Perl DevKit and have been quite happy with it. It handles modules well, and gets you a nice freestanding app. It won't hide your code very well (there are other threads regarding that) but it will let you create freestanding apps and it has been very reliable for me.

As for why merlyn, I like not having to update all of my machines perl versions just to use my tools. I can also use scripts from different versions with different module versions very easily. Upgrading a module for a new tool, won't break an old tool requiring an older version of Perl or modules. To each his own, but I like it for this.

Update: Please don't get me wrong, the above is no where near the only way to manage different versions, it's just the method I like to use on Windows platforms, it works easy, and I only have to worry about "what version of what is where" on my one machine :)

"Nothing is sure but death and taxes" I say combine the two and its death to all taxes!