The Michiko Kakutani review is quickly becoming notorious; everyone is talking about how divided the opinions on Jonathan Littell's book have been and will likely continue to be. I am reading the book now, and am completely engrossed—it's the kind of book you read late into the night—and I'll be attempting something of a post about it once I've gotten further in.
For now, I want to direct you to Daniel Mendelsohn's review in the NYRB; Mendelsohn's rich background in classics and his own research into the Holocaust give him a unique ability to size the novel up, I almost said properly, but that's most certainly not what I want to say. In fact, I'm generally irritated by efforts to adjudicate who's reviewing this kind of novel 'properly' and who's "getting it wrong" by insisting that they missed the book's 'point' or are "clueless." I certainly don't believe that all interpretations of a complex work like The Kindly Ones are valid, but I don't see how one can reasonably be disappointed to see reactions like Kakutani's cropping up in the book's wake, and I find this disdainful intellectual policing hardly helpful in interpreting the book or offering a single reason why someone should read it.
Mendelsohn doesn't condescend to the book's detractors, yet is able to demonstrate what in the book eludes their grasp. It's a great review, and I think will allow you to figure out quite well whether you'd find the book worthwhile or not.