For Star Wars fans, this book can probably be reviewed in just two words: Boba Fett.
He's one of the best-known characters in the Extended Universe, and Traviss writes him incredibly well. There wasn't a single scene with Fett in that I can remember that would have scored below 10/10. The author should be particularly proud of those scenes.
On saying that, the Prologue is odd. It's from Fett's point of view, and I'd still give it full marks, but it wasn't the same style of the rest of the book (which I'm glad of, since I'm not a huge fan of first person books). It was... Interesting.
Another character that I thought she wrote particularly well was Ben Skywalker. Traviss captures the emotion of him seeing Jacen not being as perfect as he thought in a highly realistic way.
Unfortunately, the same can't be said of Jacen himself. He keeps doing things, not entirely in keeping with his character of the previous book, with no explanation for the actions. This is particularly true of the event mentioned above in which he falls in Ben's eyes. It is something which has major repercussions for the book, and it really needed some explanation on Jacen's part.
The other characters are all done farily well, although I would have liked to have seen more of Jaina, and Admiral Pellaeon, the second of which was a favourite character of mine in the first book.
There are some difficulties in series written by different authors, which is the style of writing. In most cases the series can feel disjointed. In this first change of authors in the series, I barely noticed that it was a different author.
The only indication was that Traviss uses more of the expanded universe than Allston did, which was in someways difficult. Jaina is upset with Jacen in this book, because of something that happened with the Chiss. I haven't read anything else with Jacen and Jaina and I'd assumed that the Audiobook I listened too had missed something important. But it became such an issue that I became sure that it was deeper. According to Wookiepedia (The Star Wars Wiki), the issue between Jacen and Jaina was covered in the Dark Nest Trilogy.
I felt that if there had been any sense of animosity between the two in Betrayal, I would have accepted this easily. However, the apparent return of the emotions could have done with an explanation.
And that's the only thing that the back lacks, and that's motivation for a few of the events and feelings that occur. It's not many, but enough so that it doesn't get as high a score as betrayal (Except on Amazon, where I round it up to 5 stars).
But it's a brilliant book despite this, and Boba Fett and his family are fantastic. I was a bit nervous about it not being by Aaron Allston, but Kathy Traviss has impressed me. If you liked Betrayal, you have no reason not to read Bloodlines. If you haven't started the series, so far you won't be disappointed if you start. I still whole-heartedly recommend this series.