I don't understand the use case for a sub 6 inch color ereader, which is what the mirasol is, so far. The main excitement seems to be for magazines and books with images and illustrations. But there's a reason you don't see a lot magazines, children books, or textbooks in pocket size: it's kind of unsatisfying and hence pointless. In that size, you have mostly novels or mainly text materials, like dictionaries and Readers Digest. And b&w e ink is fine for that.
Color e ink would just come off as a poor imitation of LCD. Which is okay, I guess, since you have to start somewhere, but there's a loss of opportunity cost here where less r&d money and man hours are being spent on improving b&w e ink. I want a paper white background, more gray scale levels, higher resolution. Everyone who has seen my kindle remarks on how book like it is. No one has complained about lack of color.