Impressive, helpful, well documented, easy to use and with a well styled and clear HTML presentation of the results. No need for instrumentation (coverage code preparation) in any way. Great!
An excellent, easy to use, stable and mature module for asynchronous, event driven programming. Simple programs written quickly. Successfully used in very large, long running distributed systems. Still lacking a port to Windows, unfortunately (but it is reported to run on Cygwin).
This module set makes it really simple to write own formatters - the name is a true promise.