Writing-wise, Empire was good. The prose is smooth, the characters generally interesting. The beginning chapter is (as so often) a bit rocky, but once we settle in to following our hero Reza, things go more smoothly. There are occasional and sometimes unheralded point of view shifts, but nothing really problematic. The real story is about the characters, and up until the end, that was quite good. I read the story with interest and a desire to see what happened next.
Content-wise, I had more trouble. The story, a heavily military SF novel, has a bit of an Ender's Game feeling at points, but probably leans more heavily towards Jerry Pournelle. Unfortunately, with a good deal more reverence for the military (from whom all blessings flow). Once Reza heads off to live with the Kreelan, the story turns even more towards combat. Granted, the Kreelan are a culture based around a military order, but I found it difficult to stomach the mystical attitude towards combat.
There were other flaws in the setting. The Kreelan are a high-tech species, yet live a very low-tech lifestyle. Hicks explains how that happens, but never why. An annoying tendency to use Yoda-speak have they also.
Story-wise, the major flaw was that Reza's action at the end of the book is completely unsupported, and therefore not credible.
There's nothing really new in this book, but it's a good read. While it starts out SF, it shifts heavily into seeming fantasy by the end. I personally will not be going on to following books because of the sudden and unsubstantiated ending. A less demanding reader, or one more excited about military stories might find this worth checking out.