I’ll be honest and say that Google Analytics is intimidating and way more complicated than I need for my average website. Also, I don’t love having yet another third-party resource hooked in, particularly one as divisive as Google. WP Statistics is self-contained, so no data is sent anywhere else. It’s comprehensive enough for me to understand traffic to the site and configurable as well. I like that it’s open source and hosted on GitHub. I haven’t seen any performance issues.