I accidentally found Duolingo through an app search on my phone and so glad I did. Why haven't I heard of it before!?. Duolingo is far far better than Memrise and other apps out there!! I have already recommended it to a handful of people who have all signed up and agree its a great learning tool! Well done.
While I agree that Duolingo is better than Memrise, it's not really fair to compare the two. Memrise is a website that uses SRS for learning whatever you want (Including non language related things, though most people use it for vocab) and should be treated as such. It's never gonna be comparable to Duolingo in it's scope, but I still love Memrise and use it alongside Duolingo.