The audio and repetition are what really stick out to me. It always helps to hear the correct pronunciation of a word in order for it to stick with you. Repetition is also key. Combine the 2 and you've got a great piece of software.

I have used a variety of language-learning softwares and Lingvist is the only one to stick out to me. I am both a French and Medical major, and have lived in France for over 3 months. Since I have been able to use Lingvist to learn practical skills beyond grammar, such as read French jokes and listening to non-academic (boring) sources. This application does what others can't by offering both memorization based grammar and also more interesting culturally French elements like humor.

The adaption tools that change the pace of learning the language to match your level and skill, which is a great way to keep going at a pace that isn't far too advanced or far too easy.