I bought this book for my son for Christmas, because he had just gotten into reading the Left Behind series, and we've somehow misplaced this book. It wasn't in the library, either, although all the others in the series were. So, we had to complete the series. He didn't want to read any more until he'd read this one, and yes, it is slow, and feels like it could have been a couple of chapters added to the last book, or a couple of chapters beginning the next book. It didn't need to be a whole book, and it definitely does not "stand on its own" as a book. I will say I recommend this book, but only for the reason that "you have to complete the series."
It wasn't that bad. Ok, so it was kinda slow and some of the dialogue for the resurrection scene seemed forced and purposfully dragged out, but it was still pretty decent. But not nearly as good as Assassins. I mean, let's face it, we all knew what was going to happen during Indwelling, but Assassins kept you on your toes. If they Jerry Jenkins and Tim LeHaye can get back to that kind of suspense in The Mark, then it will be exceptional. So far, this has been the lowest ranking (in my opinion) of all the books, but it's still decent. Read it if you want to keep up with the series, but don't make this the first one...start at the begining. It'll make things a lot clearer for you.