I can't make my mind up about Duolingo. It's kind of good for certain bits of vocab but does take up a lot of time. As for another user I thought memrise was more useful for me.
For a humourous view of Duolingo see
View: https://www.youtube.com/watch?v=BbmXSR_QiP8
For a humourous view of Duolingo see
View: https://www.youtube.com/watch?v=BbmXSR_QiP8