Although I love some of Ian Irvine's other stories, specifically the View from the Mirror and Well of Echoes series, I have to admit that upon reflection, this trilogy just did not grab me as much as the others did. The lore and the world itself were really well done, as you'd expect from reading Irvine's other work, and I particularly enjoyed the idea of the Engine and the Kharon/Kharoon - this seems an oddly familiar word from another series, are we hinting at something Ian? Very clever if so!
As stories go I thought the plot was interesting and had plenty of twists both major and subtle. The hints at connections with certain characters and races from the other series was most enjoyable. For all this though, I didn't particularly like any of the characters. I love flawed characters and anti-heroes as much as the next guy, but certain characters were so flawed and behaved in such outrageous manners that I didn't really find them believable. Holm is one of my favourite characters in this regard, as I found him the most down to earth - similarly, Axil's character remained consistent throughout the series and even had some considerable character development during this final book which I really liked. Glynnie and Tali behaved fairly ridiculously at certain points though - I guess it could be argued that given their extraordinary situations, they're bound to behave strangely, but for me they simply crossed a line.
I won't spoil the ending by revealing specific details, I'll only say that most of the main plot points throughout the series came to their conclusions, and most were satisfying. The two 'big' twists felt a bit cliche to me, but I suspect that's just personal preference. I'd probably give this title a 3.5/5 if I could, but as it stands, it just doesn't do it enough for me to give it a 4.