I've had my TOC in the back. The reason being: my chapters don't have names. There wouldn't even *be* a TOC in a print book (and in my print book, there isn't!). But the TOC has to be there in an ebook because it's the only thing that allows someone to "flip" to a certain page.
Most people, in searching for an ebook TOC, do GoTo->Table of Contents. They don't do GoTo->Beginning and then page forward. Thus it makes sense for my TOC to be in the back. It prevents readers from having to scroll through two pages of "Chapter 1, Chapter 2, Chapter 3, ..." at the beginning, which gives them no useful information and might leave one wondering why a book with no chapter names even has a table of contents. (In the Campbell antho, I did put the TOC in the front, because it contained useful qualitative information for browsing the book.)
It's been pointed out to me as a result of this kerfuffle, though, that another good reason for not putting TOCs in the back is that it can eff with the "furthest page read" function across devices. So maybe it's good that I'm having to shuffle things around. But this is a terrible pain for me; because I can't make the books as aesthetically pleasing as I would like putting the automatically-generated TOC in the front, the end result is that I'm going to end up downloading and learning new software and inserting a custom HTML TOC in the front rather than the automatically-generated one in the back, and all for something that should not actually be an issue at all. As has been said upthread, this has been a recommended standard for ebooks before; the fact that Amazon suddenly thinks it's a problem -- and is removing books with no warning -- is egregious.