I tried EnglishCentral for a cousin of mine. Her exact words - One of the best ones out there.

1. Quick and easy signup with online material available over the internet to access the resources from anywhere 2. Short videos with subtitles to understand the content 3. Step-by-step videos help understand the solo description and the conversation between two or more people. 4. Choosing different levels of difficulty is helpful 5. Clicking on the words, I don't know, gives a popup with audio and description helps understand the content well. 6. Pronunciation of difficult words during the video is awesome 7. Tutorials classification for different purposes & Good vocabulary collection and Go Live feature