Meh, when you say Duolingo isn't great, you should compare it to something in its same class. I don't think Duolingo competes with sitting down with a grammar book. The whole reason I used Duolingo, which got me up to speed with Spanish enough to read books, is that I could do it anywhere and any time rather than bust out a book for serious study. I was never going to do that, so Duolingo was strictly better for learning a language than a book.
People lose track of that every time they dunk on Duolingo.
