I boycott buying books from all Macmillan imprints, not because of agency pricing, but because of their refusal to sell ebooks to libraries.
It is strange. Libraries actually pay more for each copy of an ebook than we do for a hard copy. There is no discount. We pay the lowest hard copy price available. If the book is only available in hardcover we pay the hardcover price. If it is available in mass market then we pay that price. For hard copy books we get a deep discount. Plus like hard copies, each "copy" we buy can only circulate to one person at a time. Unless someone breaks the DRM, the book cannot be read after the circulation period.
So in many ways the only difference is that the profit margin is BIGGER from selling ebooks to libraries.
Also got to say I will not feel bad about pirate editions of Macmillan ebooks. They deserve it.