This is, IMHO, hands down the best book in the series. And its a pretty good series. To suddenly see the prior five books from the flip side is not only fascinating, it ties the events in them together and then stands them on their head.
While you may have been told that this series doesn't need to be read in order, this is is only partially true. While books 1 - 4 CAN be read this way (although things will make a great deal more sense if you just read them in order), books 5 - 7 MUST to be read last and in order or the entire series will be spoiled.
I find it highly amusing that the final two books, which originally Mr. Anthony wasn't planning to write because he didn't think anyone would want to read them, ended up being far and away the best in the series.