In general I really like the app. The range vocabulary is very good and the repetition really helps build your knowledge.
My only complaint would be 1) The percent fluet is very random and frankly inaccurate and 2) The app does not properly deal with changes in time zones. When I am traveling, I often lose my streak. Why cant the app consider the time on your phone rather than a "Home" time??
Coucou Katie about Duolingo Learn Many Languages for Free, v5.0.14