Google Analytics isn't perfect (not meant to do cohorts or track users), but it's free and it can be used as a comparison with your server logs and other analyt

Google Analytics isn't perfect (not meant to do cohorts or track users), but it's free and it can be used as a comparison with your server logs and other analytics services. (If the delta is very small, it means you have a good implementation, if the delta is large, maybe there's a problem in the implementation) Besides the ones you mentioned, if you want to host your own analytics service and customize it, you can look into Piwik or Snowplow.