As well start with the only negative I would say that the vocabulary is sometimes a bit complicated, especially in manga thumbnails. Do not panic, it is not necessary to retain all the vocabulary.
For the rest, the lessons are well structured and read quickly. Some grammar points are advanced but they allow a better understanding. Summary tables are available regularly, so it is not necessary to make records. For the revisions, simply read the tables, and if you have a doubt, one quickly finds the information in the lesson.
FYI I am 26 and manga thumbnails are not specifically oriented to children, they give particularly good illustration of lessons, with some detailed points in the comments of each thumbnail.
Nevertheless, and regardless of the method you choose, the important thing noted is that we should not one but two learning methods (at least). Simply because the brain learns faster when he found information in common in several different sources.
And have tried many methods, I highly recommend this one as one of two methods to buy.
