Anyone has managed to learn any language using a language learning app? Please share your experience (which app, language etc)

I've got some basic Spanish down using Memrise. I've also saved and practised parts of the Memrise content in an app I built a couple of years ago:

An app I like but haven't used very much yet is I believe it's made by an independent developer.

Cloze Master looks cool, learning in context can help though I think every app does this to some extent. I have currently started with Duolingo, will use it for a few days before trying something new.