Comparison of some different mostly free GeoIP APIs I found around the internet.
Go to https://geoip.emrik.org to do your own benchmark or lookup an IP address using multiple APIs.
Accuracy is harder to test. But the only service that seems to achieve intercity tracking is ipgeolocation.io in my limited tests. Test on https://geoip.emrik.org to see for yourself :)
Feel free to add any APIs you find to the list by creating a pull request or an issue.