A very good hunt, friend! Here's my opinion:

Pros:

• You can learn a lot of languages (14 in total).
• With the short lessons you can manage your time and learn with practical exercises of 10 to 15 minutes.
• Courses with different levels and learning speeds.
• Quality references confirmed by the media such as The Economist and PC Magazine.

Con:

• Still, if it's expensive enough. Your cheapest subscription is about $13.