I recently got Legends 10: Swamp of Secrets and I will say it's a good book. Not exactly my favorite of the books but worth the read

I wouldn't say its a spoiler to reveal there is basically two stories going on in this book. It's interesting how it flows between the two stories but the final result feels like a book that's half as long as it should be and we only get a few fights and some secrets revealed. I believe both stories had the ability to carry two books, and had thy not been crammed together they would have been great individual stories.

And if your new to Bionicle world be sure to bone up on the old stories, this book wouldn't have been near as interesting if I didn't know the history of the Toa Mata from 2001.

The Kingdom is also really good, better than the book in my opinion. The idea of parallel universes has alot of potential and its good to see this idea used in such a way to tell a "what if?" story.