I liked this article in another thread, but I'll repeat something here I mentioned there because this the self-publishing forum and it's very highly applicable here.
First, this article is about Amazon's commercial publishing endeavors, not CreateSpace.
Second, there is a bit in the article discussing a self-published author who was offered a contract (she can't disclose details--highly unorthodox) to have her book edited and published commercially through Amazon's publishing arm.
She didn't get an advance. She's receiving editing and cover art and the title was changed, so she is getting services expected. She didn't disclose (can't) the royalties or anything, but if (and it's a fair bet, considering expenses) Amazon is offering less of a royalty rate that she got self-publishing, this is pretty messed up, IMO.
I really wish we could see a contract and at least see what their standard rate is. Anything less than what they're offering via CreateSpace is something I wouldn't be willing to recommend an author to take.
Essentially, right now they have the ability to offer a contract to any self-published author who is performing at a certain level (which they obviously know because they have the data). Yes, you'd get editing and what not, but if they aren't offering an advance and the only thing the author gets is the royalties, if the author is making less than the 70% they were being offered before, that's not right.
I don't mind the idea of an author going to another publisher and taking a lower royalty rate (especially if they got an advance...though I'd probably recommend only if they got an advance), but because Amazon controls both arms, they have a very legitimate reason to pick off the top sellers and pay them less--they make more money that way.
So yeah. I'm highly suspicious right now.