The app has a very good structure, is user friendly and intuitive. I also like the subscription model.
... however, the phonetics seem to be incorrect. E.g. for the word „igneous“ the phonetics are /ˈɪɡneəs/ instead of /ˈɪɡnɪəs/. Or for the word „effrontery“ it is /eˈfrəntəre/ instead of /ɪˈfrʌntəri/. As I need the phonetics to improve my pronunciation, I decided to delete the app. I am also not a language professional, so maybe there are different schools of phonetics (?!) ... Nonetheless, it deviates vastly from what I learned back in school. Thus, it just did not make sense for me.
On the other hand, if you do not care about phonetics, you will enjoy this dictionary.