From my use in London, out of Google Maps, Apple Maps, and Citymapper, I've found Citimapper to be the worst. They're all basically working with the exact same

From my use in London, out of Google Maps, Apple Maps, and Citymapper, I've found Citimapper to be the worst. They're all basically working with the exact same data, but I find Apple Map transit directions to be the easiest to use, providing I'm in one of the limited cities it supports.