OP and /u/Cobblar, these views are not necessarily my own, but I'm going to try to distill his argument here:

His big point on this was about how the variance within a racial group far exceeded variance between racial groups. Each race essentially has a wide spectrum of IQ and they overlap substantially. Sam guides this along to say, "for any trait, there's substantial overlap...there are blacks that are smarter than most whites...." The takeaway, then, is that you can't look at the color of someone's skin and say, on that basis alone, that they're smarter or dumber than someone of a different color. To do so would, you would have to be in a world where the IQ spectrum for one races was wholly above or below another.

He thinks this work is beneficial because his findings require you to look at people on an individual basis - being that their group membership is inadequate to make a determination. This leads to a society in which we deal with people more fairly. This is a double-edged sword though - his data also points to a noticeable IQ disparity between whites and blacks.

Personally, I believe the key to this kind of data being useful (assuming it is accurate) is how it is presented to and understood by the world. Knowing how we are as humans (and people's response to this book), I think we are going to cling more to the fact that there is a disparity across races than the fact that there is a lot of shared territory on the IQ spectrum.