Good, but... A lot of the English translations are incorrect. Also, there are multiple ways to say certain things and sometimes more than 1 word will mean the same thing, but the app will mark it wrong.
Great App! Great (free) app for practicing Japanese. I'm 5 chapters deep into Genki and this app is perfect for my level. I was looking for something that let me do some sentence drills (instead of straight single word flash cards) and this does exactly that. So far, I haven't come across any words that I haven't already seen in Genki, so I'm guessing that the creators intended to follow the text pretty closely.
Very good. I like the simple material user interface. And I like that I cab practice on random sentences. Very good program, and very good it is open source. I'm curious where will it evolve. Great. Very good.