It’s definitely a good one
It is very precise, with several options to both keep up with your level and also with words you want to practice. The only part I didn’t care for is constantly asking to add to my list when I made it clear of my choice, and the speed to the words being spoken. Still a very good app.
Response from developer
Thank you so much for your feedback, we are very happy to hear that you like the app! : ) We also value your technical feedback. Would you drop us an e-mail at support@merrymandarin.com with an example / screenshot of the points you mentioned? Perhaps this is something we can solve for you or improve in a future update.