Well, let me be the next to offer an uninformed opinion about Amazon's apparent parting of ways with Macmillan and its imprints like St. Martin's, Tor, Forge, Henry Holt, and more. The prevailing information points to Macmillan balking at Amazon's ebook price of $9.99, favoring a higher royalty rate. Publishers also prefer a delayed ebook release to protect hardcover prices and selling window (since paperback versions are generally released 9 months or so later, the hardcover crowd has usually made its purchases).
The Apple iPad announcement, which seemed to have all the publishers lining up in anticipation, would set an ebook price of $12.99 and up for Apple ebooks. The publishers apparently pushed all their chips to this bet. Unfortunately, they seem to have forgotten that Amazon is the world's largest bookseller. Publishers need Amazon far more than the other way around. Amazon doesn't need books. It can sell razor blades, underwear, Apple tablets, DVDs, televisions, camping gear, practically anything. Publishers don't have a whole lot else to sell but books.
I understand the publishers drawing a line in the sand. Unfortunately, consumers don't support it at all. The only people who think ebooks should be more than $10 are publishers. Hardcovers and paperbacks have physical costs in printing and shipping. The only overhead in ebooks is editing and formatting. My main concern is for the effect on authors, because I have friends who publish under those imprints. And they're probably locked up in contracts that will last years, so they have to roll with whatever the parent company decides.
While it's hard to pick a side between Major Corporation A and Major Corporation B, it's basically a moot point now, because Amazon long ago set the price of ebooks at $9.99 or less. A number of independent authors are doing quite well with their ebooks through Amazon, most pricing them at a few bucks. Will they fill the gap left if bestselling authors aren't around, or will Kindle owners reduce their shopping because their favorites are missing? Since I currently don't have a book contract, I don't have a dog in the fight, though I do have a few titles up for Kindle. Right now I am watching and learning. As an author, I just want to reach readers. As a reader, I want as many choices as possible. Let's see what happens when the dust settles.