I have read the fist book separately the reviews will be of book 2 and 3.

Heart of a Dragon
A very solid second book for the Lucian and Arabella trilogy. There is a good amount of drama between them that really gets to the bottom of what is keeping Lucian from committing with Arabella. The side characters were also great in this, bringing some fun or common sense. The pacing was good and the resolution for was satisfying.

Fire of a Dragon.
That ending. My oh my I now see why the series is all three brothers long and not each with their own trilogy. 
The plot was good in this one but I found it not as exciting or emotional as the previous book. There was a good mixture of fun moments between everyone but also still plenty of drama to round out Lucians and Arabella's story. By the end you will want to continue on to see who the other brothers end up with.