I think the module has great ideas in it, and is very Perlish in its nature - so for I like it the most among modules launching other processes and chaining their STDOUT and STDIN.
Interface requires a bit of mental effort, but once one understands its quite functional (i.e. a chain of code references) nature, everything becomes clear and easy.
The documentation, the part that explains how Perl sees it, helped a lot - now I actually prefer the explicitly nested form (how Perl sees it), not the line form, but it's a matter of taste.
Alas, at the moment the module is practically useless under Windows 2000, but it is no more useless, than, say, IPC::Run3 - both equally don't work when asked to do very simple things.
I have a feeling that it's because of Win32 Perl + its threads, but I'm no expert.
I highly recommend the module to be used under UNIXish systems.