It’s great to see other publishers picking up on the “ebook bundle” concept and including multiple formats — the Pragmatic Programmers are now selling a combo of EPUB, PDF, and Kindle-compatible Mobipocket files for their ebooks. I especially like the way they’ve phrased it:
You’ve bought a license to the content, not to a particular file format, so you are free to enjoy that content on whatever device, using whatever display technology you choose.
Well said.