It is very user friendly as it has an easy-to-use interface and also supports several languages like Spanish or Portuguese. I love that it's free but there are many other apps out there for this purpose such as the Google Maps app which can be used offline and is more commonly known by its full title of Waze (which was purchased by Google). For me personally, nothing since it seems pretty good overall with regards to functionality etc. The only thing i don't really care about is the price - not sure why they would want to charge money at all for something so useful. But you get what you pay for! There isn't anything too majorly wrong though. If you're looking for a simple way to calculate costs while travelling then this will help you do just that. And once set up you won't need any additional software.