This package is easy to learn and is handy for making simple (or not-so-simple) charts and graphs of arbitrary datasets with just a little bit of coding. It uses GD as a backend, so it gets a lot of choices for output image format for free. It has convenience methods for PNG and JPEG output -- for others, you request a GD::Image instance and do it yourself. That option also allows you to do arbitrary additional scribbling on the image as you like, which can be handy.
My small complaints are:
* The complete docs are in PDF format. Only a summary is in POD. However, this makes some sense because it isn't feasible to embed images in POD.
* Doesn't support GD's stringFT routines for working with the FreeType library to use arbitrary TrueType fonts (I have a private patch to rectify this if anyone is interested)
* Spews version number warnings on startup
* The behavior of some of the axis options (like include_zero) are highly non-intuitive
* The scalar_png method is broken, so you have to write to a file and then read back to send out the web if you can't send straight to a filehandle.
* The source code has a lot of copy-paste redundancy and could use a thorough refactoring pass, IMHO.