I didn't like Duolingo because First: I hate flash cards and Second: I felt like a kid using it.

Watching from short videos to series and movies (depending on your level...) work for me much faster and natural than spending 10 minutes on something useless like that app.

How I use italki: I study languages by myself (for each language I develop my own method) and I use italki to improve my writing skills, to clear my doubts about grammar or specific details and to meet people which we can help each other.

=)

I tried to use Duolingo to improve my english and I don't think it worked as good as I wanted :{
I felt limited, it's always the same vocabulary