I´m enjoying it so far. I have to say, though, that it is a bit repetitive at times, especially when it comes to the descriptions how alkaloids work in the human body. She basically recaps the effect of alkaloids in almost every chapter. And it is really a bit spoilery in regards to Dame Agatha´s books. So far I´m enjoying the descriptions of the historical poison cases the most.
I very much appreciated the recaps. :D And as I use the book a lot for reference, the recaps are even better because I don't have to skip back to a previous chapter to find some of the details.
And yes, she does most definitely wander off into spoiler theory -- even when she's not explicitly saying so.