One thing I liked about the original version of this book is that it dropped you right in the middle of the action and expected you to keep up. It was a wild ride, while also being on the dark side because this world that Merq and Armise live in is total FUBAR. One thing I wasn't that enthusiastic about was the lack of world-building. How did Earth go from thousands of countries to just five? Where exactly are the borders? Why are they fighting for 300 years? Who are the leaders of the other three countries (since we know the leaders of two, but only meet one) and how are they elected or put in charge?
The second edition largely restructures the story. Whereas the first edition drops you in the middle of the action and pretty close to when the crap is going to hit the fan, with flashbacks here and there to fill in some background information, this edition is told chronologically. All those flashbacks are pulled out from the middle and end of the story and brought forward. There are a few extra chapters and an epilogue of sorts added to round out some of the things in regards to Merq's relationship with Armise, and to give us a little more information on the technology and what exactly it is that Merq is up to. One drawback to this is that we get a lot of repeated information. Some of the things we now learn near the middle of the book (which was originally the start of the first edition) come out of nowhere, when it should've been hinted at before. Then you have characters who are basically "reintroduced" even though we already met them in what is now the beginning of the story. As for all those questions I had originally? We do learn what the other countries are called and learn a teensy more about one of them, but not much else. But that's fine. There's still three more books in this series and plenty of time to flesh out this world.
As for Merq and Armise, I think the biggest thing this restructuring of the story does is highlight how extremely unhealthy their relationship is. Both of these men were picked at very young ages to be weapons for their respective countries. Armise has been an assassin since before he sprouted pubes, and Merq was raised with the knowledge that he was to fulfill one particular purpose in the Borders War and that after that his life would be forfeit. Neither of these men have any reason to hope in a better tomorrow - at least not one that they'll ever see for themselves - and they certainly know nothing of life beyond bloodshed and deceit and political maneuverings. They're fighting for opposing countries and are often given orders to kill each other. Their lives are not their own but are at the mercy of the whims of their governments.
Don't expect your ordinary M/M romance with this book. It's not there. Instead, you have two MCs who would just as easily kill each other if given enough incentive. Their relationship, such as it is, is more about defying their governments and the regimental control over their lives than it is about feelings for each other. There's lots of angry sex and power play (though not described in detail, for those squirmish about such things - which I can be), and lots of pensive brooding. So don't expect a feel-good ending or even an HFN. The best you can hope for is that both guys survive to see the next book.(show spoiler)
I originally rated this four stars but am now rating it 3 stars. That's more to do with my own personal tastes changing over the last few years than anything else.