I read a bunch of books and manga on the Forma over two weeks. Manga tend to have trouble on smaller e-readers because some of the English annotations can be quite tiny, but even the tiniest text in a CBZ version of Kiyohoko Azuma’s Yotsuba&! (a family-friendly book about a cheerful, possibly alien five-year-old) was totally readable.
I assumed a larger screen would be better for manga, but it was useful to have someone validate it.
I’ve just put in my preorder for a Sage after a year of indecision. I’ll report back how I go.