When I read this book, it gave me the vision that I was actually watching the fourth Star Wars movie that never was. I personally thought this was a very solid book, however not great. The new introduced villain of Xixor was excellent. Only Grand Admiral Thrawn of the Timothy Zahn Trilogy is better.
The familiar characters in the book were very believable to what we have come to expect of them. Luke acted like Luke, Lando like Lando, and Leia, Leia. The only character that I can complain about was Dash Rendar. One of the many curiosities about this story for me (that is, before I actually read it) was to see what a Star Wars novel without Han Solo would be like - but Dash Rendar was too much of a Han clone. And the way his fate is sealed - much too sudden. The author could of did much better with that one aspect.
While the character of Dash Rendar was really the only negative I could find, I thought the conflict between Prince Xixor and Darth Vader made this book worth the read... and you can't forget, the Emperor, plays an important part too.
However, between the movies The Empire Strikes Back and The Return of the Jedi, I was always confused of how everyone ended up where they were. For example, how did Lando become a "guard" for Jabba the Hutt? I thought Chewbacca was with Lando when they left together at the end of The Empire Strikes Back. At the start of the next movie, however, Chewie is walking into Jabba's palace with Leia and Lando seemed to be there before they even arrived. This book doesn't resolve any of these or other conflicts of character placement, (except a few minor ones).
Additionally, they could have done more with Boba Fett, he is always a character that can never have too much "page" time. However, it still was a very good book and I encourage you to read it. Unlike Kevin J. Anderson's books, this one actually has a fairly developed plot to it.