I had some hairy code to colour using gvim, which kept popping up some gvim windows and interrupted my flow. Then I switched to this module, and now there are no popups, and my code is so clean it's not even funny. Highly recommended for all your vim colouring needs.
Just like any module should be: Doing a single job very well. The interface couldn't be simpler and it's well documented. It's also the only module around that can be used to programmatically syntax-color sourcecode of virtually every language (well, of those that vim can handle which are quite many).
Downsides are its speed (this is vim's fault however) and some problems when interrupting a running script with ctrl+c or so (some vim instances will keep on running and eat a lot of CPU). Nonetheless, this is a real CPAN-jewel.