[tropdrop]

I have not found Duolingo valuable for learning a language from scratch – my experience with German, in particular, was terrible. Then I tried to do Japanese with it, and trying to use it to learn Japanese from scratch was also terrible.

However, after I took a couple of years of real (institutional) coursework in Japanese, and needed to just get a little better at recognizing proper grammar constructions, it actually proved very useful – at the paid level, anyway, where one can "skip"/place into higher levels – and it seems their Japanese module in particular has drastically improved in the last couple of years.

So my two cents are that used for language learning alone it's pretty useless. But used as a reminder aide for concepts already learned it can be a good app, especially to just hear how one might phrase a sentence more "naturally" (for a Japanese ear).

For Kanji, though, WaniKani is king.