Keeping it sweet and short: The plot was SO good, definitely at its best so far, same with the writing. We followed four main plot lines, some more intertwined than others. The new characters and world building are (or seem) well developed. Besides that, the atmosphere was great and engaging. So far, so good.
Enjoyable read but it couldn't light that five-star-read flame. While Crown of Midnight was really emotional and intriguing (but with its own individual faults), Heir of Fire felt mediocre and "neutral" to me. I just wasn't THAT invested. Still excited to continue the series.