Simple to use and extremely powerful.
Works precisely as advertised.
If you need to scratch the "this is taking way too long..." itch, then this is the module for you.
(If you need to profile even after die/SIGINT/etc, see 'sigexit=1')
Clear doco allowed me to jump right in and debug some hairy global destruction issues in a complex (Moose, AnyEvent, ++) codebase.
Worked exactly as advertised.
I'll also remember this module if I ever need to hook into a running perl process.
While I have not had to return data from my processes, this module was clearly documented with an out-of-the-box synopsis and has simplified working with forked children for me.