Awesome! Duolingo doesn't have Korean yet, but I wasn't impressed with their Spanish.
Not sure exactly what you mean about the characters. So far Mango is exclusively using the phonetic Hangul alphabet, which is not ideographic. I doubt they would ever use Hanja. But yeah, typing could be an issue! Didn't think of that. I don't know if Mango ever requires me to type a response though? Only on lesson 1. We can install the Korean keyboard on the computer, but I could see that being a problem for others or when on my phone. But I'm not too worried about learning to write well, since my husband and in-laws will teach our daughter that (doubt I ever get that far). I'd just be impressed if I could carry on more than a two-word conversation without my SIL translating. Does Mango go beyond conversational lessons and into reading and writing?
No, I don't think Mango goes into reading and writing; Rosetta Stone is better for that. It's good for me as a supplement to RS and my workbooks since I don't have to unpack it (ha), I can take it anywhere, and the Auto Play lets me go through a lesson hands free (wish it could be a whole chapter, though).
For anyone wanting a comparison from my personal experience:
Rosetta Stone: (I have an old version) Good for all around learning though it can seem tedious at times. I like that it forces you to learn the language by making logical connections (they call it "dynamic immersion"), like in real life. Keeps track of what you get wrong so you can go back and review those sections. Exercises are multiple choice using pictures or a combination of pictures and words and matching. I never used the writing aspect or speech recognition feature. Can be expensive for a full set even with discounts.
Duolingo: I stopped using this awhile back after an update made the UI less sleek, though they may have fixed it by now or it could have just been an issue with my old phone/iOS. The game aspect of it is fun, you can track your progress against friends and it records your streaks. You get points for lessons you learn (points deducted with each wrong answer) and it shows you your progress toward your daily points goal. I like that it had "strength" bars to gauge lessons based on completion or how long it's been since your completion so you know to go back and review. Variety of activities (typing responses, multiple choice using words or pictures, correctly arranging words). The audio quality was not very good, however. Free to use.
Mango: I use this now and it's very straightforward -- lessons/chapters/units, no games. Audio is better than Duolingo (still not perfect). The only exercises are recalling a translation from memory and multiple choice; the multiple choice is ineffective as it's not challenging at all. As I mentioned, I like the hands-free Auto Play feature (which is just memory recall, no multiple choice) but it stops at the end of each lesson so it goes by pretty quickly. I like the notes on the language and culture that are included with the lessons. Does not keep track of what you get wrong like the other two. Free to use with your library card number if your public library is on their list.
Sorry if I left out or misremembered anything, I have a notoriously bad memory.