Iron Flame hooked me from the very beginning and I resented every time I had to put it down for work and sleep.  Despite a few criticisms I had a really good time with it.  I adored the main couple as much as I did in Fourth Wing and the dragons were awesome. 

The book is divided into two parts and sadly they're not equally good. The first part I adored and if I was rating that part alone I would give it five stars. Part 2 was mixed. I enjoyed it and there were some really great scenes and important revelations, but there was also one particular section that bored me, and a new character seemingly introduced in order to create drama between Xaden and Violet.  The latter felt both annoying and utterly needless as their relationship already has plenty of obstacles to overcome. 

I was expecting a twist at the end after Fourth Wing, and the one we got leaves me slightly concerned for book three. If written right it could be great, but there are multiple examples of books that have done similar plotlines that I haven't enjoyed at all. I really hope that Yarros has a good plan for it, preferably one which does not reverse any of the character development from Iron Flame. 

Overall I really enjoyed this, even if Fourth Wing is still my favourite of the two.