The most significant difference from Duolingo is that people get results with it. I’ve known literally hundreds of people who have put real time into Duolingo, over 10 hours a week for years in a few cases and zero of them have actually learned a language to a B2 level or higher through that massive time commitment. The best case I’ve seen is from people who accumulated a back of memorized word translations and grammar patterns through Duolingo and then spent time reading and listening to content that included them. Even those people learned slower than those who just focused on input from the beginning, though.

In contrast, I don’t know anyone who’s put 10 hours a week into Math Academy for multiple years but those I know who have done it for 6 months have made considerable progress, sometimes the equivalent of years of course work.

Duolingo’s flashy animations and casino-style gamification techniques are actually a negative signal for an educational product.