Blood of Dragons is the final volume in the Rain Wilds Chronicles, and I think it was a solid ending to a somewhat shaky series. Like the other books in the series, it starts a little slow, but it quickly picks up the pace. All the characters get some resolution to their plots, we learn more about the relationship between dragons and Elderlings, and there is quite a bit of action and excitement. In fact, I think the last 200 pages of the book are probably the best of the entire series (though not the best Hobb has ever written).
One thing that I didn't like about the series up until now was the seemingly disparate plot threads that never really seemed to create one cohesive story. In this book, I was pleased to see that the Malta/Reyn subplot and the Hest subplot were finally joined with the major story of the dragon keepers at Kelsingra. However, I was disappointed by the conclusion to Selden's story. I feel like he could have been left out of all the Rain Wild books completely and it would not have hurt the story at all.
The conclusion of Hest's story was shocking and not anything I would have expected out of Robin Hobb, but when I think about the character, it is definitely completely appropriate. It's good to know that after so many of her books, the author can still surprise me.
If you have read the first three Rain Wilds books and are wondering if it is worth reading the final installment, I would say yes. It definitely does justice to the story and adds insight into the world that Hobb first created in the Farseer trilogy. If you haven't read any of the books, but are a Hobb fan, then again I would encourage you to read the Rain Wilds Chronicles. I think the series as a whole is much better than the individual books standing alone. But, the Rain Wilds Chronicles is still not on par with the Farseer, Tawny Many, or Liveship Traders trilogies.