I generally like this app quite a bit. It has a huge vocabulary, and good ways to study and learn the phrases and vocabulary.
But, my wife who is Korean says that some of the translations are awkward, or antiquated.
One of my complaints is that they don't tell you the part of speech of the English word, or which meaning of a word that has several meanings. For example, the word "present" can mean "gift", "now", or be used as a verb, meaning to give a speech or lecture. This app doesn't distinguish between these meanings, it just give the Korean equivalent of one of these meanings without telling you which one.