Earlier today, I wrote about a problem I'd seen reported via CPAN testers. A test was failing on Cygwin, probably because of Cygwin being weird. As expected, I was able to talk to one of the intrepid CPAN smokebot operators, ask for help, and get the problem resolved very quickly.
I think I fix as many, or more, bugs because of CPAN tester reports than because of reports by users. Not only do they donate CPU time on test boxes, but they donate their time to setting up those test boxes. Then, on top of that, they've often been very accomodating when I've asked for help nailing down and fixing a problem on a platform to which I have no easy access.
So, thanks! Chris Williams, David Cantrell, imacat from Taiwan, and everybody else who has helped me notice that I write broken software: you guys rule.