Citymapper

Citymapper is a great, free navigation application.

What it does well-
Citymapper can be very useful when traveling in many cities. It provides various transportation options such as walking, biking, train, or bus. Also, when using the train, it will tell you which exit to use from the station, possibly saving a few blocks of walking. It can also provide transportation options that will be cheapest, keep you out of the rain, or be the quickest.

What it could do better-
Citymapper is only available in a select number of cities. When traveling outside of those cities, Citymapper offers no navigation or suggestions of any kind. Until Citymapper expands its availability I would suggest using Google maps when visiting a city where Citymapper is not available.

Bottom line-
Anytime I am in a city that offers Citymapper I use it. However, whenever I am outside of Citymapper's coverage area I use Google maps, which is almost as good.