I agree with fluffy that these Opening books are definitely the best on the market currently and the Anand series is the better or I should say the most convincing of the two.
Despite the above however and as I am fond of saying, there is no such thing as the perfect repertoire or perfect Opening book, or even perfect chess book.
Specifically dealing with the Kramnik series I can say there are some big holes in some of the analysis, but such is to be expected with a project of this scope. As a Kings Indian player I was curious and concerned to see how convincing his analysis was going to be for the White side, and I'm happy to report that KID is still alive.
Sticking with the KID a little while longer, I would like to point out an important ommission that Khalifman fails to address, Namely the following move order:
1. Nf3 g6 2. c4 Bg7 3. e4 e5 4. d4 exd4 5. Nxd4
Nf6 6. Nc3 O-O 7. Be2 Re8 8. f3 c6 intending d5 with a good game. In fact black is a tempo up compared to a similar line in the KID as he has not lost a tempo on the move d6.
An FM friend of mine following the Khaliman/Kramnik repertoire against an Austrian IM, found himself in the above line and got absolutely zilch as White. Checking the book afterwards for solutions, he discovered there was none!
I eagerly await the Sicilian installment of the Anand series so that I can compare it with 'Experts vs The Sicilian' which by the way is another 'Topnotch' book.
There are few more soft spots I could point out in the Kramnik series and for that matter the Anand Series too, but I think I will use those discoveries to rack up a few points first.
To clarify my position, I would state that despite one or two inevitable analytical mistakes and ommissions, Khaliman's Anand and Kramnik series are both excellent and a must have for any serious Chess Players library.
Topster