Harry Potter and the Second Question of the Week

As many of you know, I recently read and finished the last Harry Potter book. Since I'm at sea, I didn't have access to a hard copy, and read an electronic copy that had leaked onto the internet a few days before the book came out. The copy I recieved turned out to be real - aside from a couple of typos, the leaked copy was identical to the real book. However, imagine that things had gone a little differently - what if the supposedly "leaked" copy of Book 7 was really just extremely well written fan-fiction? Would it matter that the ending hadn't been written by the original author? What if the fake book was better than the real book? Discuss.