I enjoy using Memrise to learn Korean and have recently started learning Mandarin as well. However, I am disappointed in the fact that the courses use pinyin instead of the characters as the main part. The characters may be featured, however, they are at the bottom of each word ‘flash card’ I should say. While the pronunciation and tones are important to note, so are characters if we want to recognize how to read.
If you haven’t already found this, there seem to be several user-created courses under the Chinese-traditional category.