As the question suggests, I'm looking at installing Piwik to monitor my sites. Currently I'm using Clicky, which works well but I'm reluctant to upgrade to the paid version.
Does anyone have any experience or advice about this application?
Piwik is a good stat tool. It isn't as beautiful as GAnalytics, but does its job well.
One thing to note: if you're using it on a high-traffic website, it's better to setup a separate instance to server piwik files.