Just a few hours ago I finished the ROTS novelization. I felt that the book had its ups and downs; I'll start positve:

1. It's really interesting to get inside the character's heads at crucial moments.
2. There are additional or deleted scenes in the novel that make the story have more cohesion and meaning.
3. Some of the dialogue is different, sometimes it is better than the movie, but most of the time (see below)
4. Some scenes are more drawn out, obviously from an earlier draft before the script was a little rushed.
5. Palpatine Rocks! (Okay, that's not a reason, but I had to say it).

Negative:
1. The dialogue replacing the movie's is usually a lot, lot worse
2. Some of the added scenes are just plain weird (Yoda pretending to be a baby, with Obi-Wan as a hunchback trying to get into the temple, yes you read that right)
3. Some of the force/combat dialogue goes on and on
4. Did I mention the wonderful intermissions Strover has? For example, during the space battle he stops and goes "This is Obi-Wan..." for 2 pages, then 5 pages later "This is General Grievious.."--I utterly despised them
5. Some of the most important scenes are cut out, for example the entire battle of Kashyyyk, most of the Yoda vs. Sidious duel, Order 66, the Mace vs. Palpatine fight (you get the picture).

Overall, the book was a good complement to the movie in some ways, but do not buy it, just rent it from a library or friend. Unless you adored Shatterpoint, Strover's writing style doesn't seem to mesh with the ideas he's trying to present. (End Rant)