Mostly great. Entirely free if you don't want to spend, but the app is trying hard to get you to monetise. And that's fine, it's a business. However the reason for my 2 star review is there is an app breaking bug when it comes to pronunciation exercises. The app ignores voice input and gives you a red mark, impeding your ability to progress. I've tried the app on multiple devices with native speakers, and it always results in an incorrect answer. Please fix!