Well, I read this in (mostly) one go, and it's .. well, (expletively) amazing. The drama is excellent, the character interactions and revelations.. maybe it doesn't fit into a stereotypical type of manga, asides from the rising-artist's-tribulations sort of thing, but it's worth reading. I thought it was actually BL, but it's not, though you still shouldn't read this if you can't handle the mature themes.
It's not like shoujoy smut where everything is all lovey-dovey, and the couple ends up together for the rest of their lives, etc. I think the most touching and brilliant part of this manga is that despite the fact that the realities that the two main characters experience are different from ours, Nihonbashi-sensei portrays it in a shockingly realistic way. She isn't afraid to pick through the thoughts that are usually absent from manga--there's shame, the complexities of love, and shattered pride, and self-hatred... It's not just a manga-approach to the world of manga creation, but a story trying to get at the heart of what it's like to have to define and discover yourself.
The art is really good, though I hate Machizo's hair. XD It's a very interesting and distinctive style, reminds me a lot of anime, though not really- it has a crispness and distinctness that sets it apart (asides from the fact that it's, you know, printed as opposed to animated xD).
But, it's amazing. The plot is great--keeps you twisting in your seat the whole way through. I wish I could finish it, since it's simply so good so far that I can't imagine the ending..
Even if you like shoujo, or shounen, or don't care about slightly-off-the-wall mangas, you should at least try to read this. The plot is great, the characters are amazingly portrayed, and it's just overall wonderful. (Though if mature themes squick you out, it might not be such a fun ride.. XD; Just a warning!)