I've just finished the book and thought that it was very good!. I thought the plot was good, the Squales fascinating and the characterisation spot-on. The only negative for me was the science -- it was over the top and pretty difficult to understand. All in all though a very good book.
What concerns me though is the whole Titan saga. I'm getting sick of Riker and Troi getting separated and one of them thinking the other is dead and then, oh wait, they can sense each other, they'll be back together soon!
Also how many more times is Dr Ree going to go completely off the rails and do something stupid which will involve violence, kidnapping and/or breaking the prime directive?