We are currently considering acquiring a Web Analytics solution for our on-premise SharePoint infrastructure consisting of pretty much all the latest versions of the platform: 2010, 2013 and 2016. The reason is beside the point but suffice it to say that we do not consider the SharePoint analytics features to be anywhere near enough compared to what the latest solutions on the market have to offer.
After having carefully reviewed tons of various systems (many of which, such as Google Analytics, do not fit the on-premise model), we found that only a handful of them claim to provide SharePoint-specific features/reports. Most of these systems dismiss the issue on the grounds that SharePoint sites are, after all, well... web sites and that there's basically nothing special out there about them, except maybe developing a few additional reports.
There are however other systems that take the SharePoint market segment pretty seriously and offer dedicated solutions for "integrating" their web analytics solutions with SharePoint. One such example is Piwik with their support for the Minimal Download Strategy...
So, here is the question: how justified is this integration argument? Is it worth the money or any other decent enough solution out there could be easily adapted to SharePoint by just specifying a few additional variables and visualizing them in custom reports?