Re: Duolingo vs Memrise vs Babbel vs Busuu
I've been doing Duolingo steadily for the past two or three years. In fact, I currently have a 508 day streak. I actually started using it earlier, but my streak got broken. Now, I've been only doing this about twice or three times a day---so I'm not fluent in French, and I'm sceptical of Duolingo's claims that I am 52% fluent in French. But...
But...even with a little bit of practice, I notice significant improvement. I now know by ear the difference between "un" and "une". Also, while I'm not perfect at it, I can hear the differences between "é" and "è". I'm also surprised to learn that even when I'm stumped and don't know a particular word, I can make a good educated guess as to the rest of the sentence and I'm usually right.
Duolingo by itself will not enable you to learn a foreign language (and if I were teleported to Lausane, I know I will quickly discover how much French I *don't* know), but I think it is a big help and I recommend it. (I haven't done this myself, but I think that if you participate in group activities where you write something in French or correct somebody else's French, you will get much more out of Duoling.)
P.S. For the heck of it, I tried German, and from the feel of the first lesson---it's a much tougher language to learn. Not impossible, but tougher. If I ever get back to it, I may ammend that statement, but my sympathies for anybody who will have to learn the difference between "der", "die", and "das" as well as essential non-obvious words like "entschuldigen" that don't exactly roll off the tongue.