I read it. I liked it, though I think it was dry in spots. I generally like Luceno. He's one of the better Star Wars historian authors to me. I've liked how he has linked the EU and movies together in his books before. He does a lot of that here, and I think particularly with his own books, and it might be a lot to take for readers not well versed in the EU. In fact, he might do a bit too much linking everything together.
I liked Plagueis for the most part but I wish the book had focused more on him. And I wish there had been at least one Plagueis fight with a Jedi. The book spent more time building up Palpatine, which I didn't mind so much because Palpatine is my favorite Star Wars character. I was surprised how much of his family and history was written about though. I was wondering if Lucas was going to keep that stuff a mystery, but you get a good dollop of it in this novel. I do have a gripe about them not giving him a first name though. Palpatine quickly outshined Plagueis, and they might as well have renamed the book Darth Sidious.
Dooku, Maul, and Anakin also have cameos, sometimes long cameos, in the book. And Luceno also names several other Sith Lords, including Tenebrous, Plagueis's master and others further back. But for some strange reason he never names Tenebrous's master yet names other Sith that preceded him. It's a small gripe but I know that couldn't have run out of names. (For me, I'm a big fan of the Sith, especially the Bane line, so I would like it to be as complete as they can make it).