Short review because it's late and I'm sleepy but if I don't do this now I'll forget to do it later:
Tarkin has a completely different tone from the other new canon books I've read to date. Several things set it apart, such as good writing (yay!), really good characterization (double yay!), and a cohesive plot that flows smoothly (frickin' triple yay!). While Luceno's prose occasionally slips into purple territory, his portrait of the Empire's first Grand Moff is a compelling one and he managed to capture that "This is Star Wars!" feeling that I didn't get from A New Dawn and Heir to the Jedi.
So thank you, Mr. Luceno. May you get more Star Wars book contracts in the future. If you want them. No pressure. ;)
In general, I have great respect for James Luceno as a writer. But then he pops out a phrase like this:
Teller made his eyes bright with mystification.
I mean, I get why some writers avoid the whole "wandering body parts" thing like the plague, but now I'm picturing this guy physically straining to make his eyes shine to convey his mystification.
Oooh, look! Twilight is super mystified! :o