For London at least, better routing, more accurate timings, and also accurate updates on things like strikes. It used to be significantly better but Google Maps

For London at least, better routing, more accurate timings, and also accurate updates on things like strikes. It used to be significantly better but Google Maps released an update a few years ago that makes the gap relatively small though, but it is still better. It's also surprisingly useful to have two mapping apps on mobile devices which otherwise make it difficult to have two separate routes open at once.