I think your perception is correct, but I am no expert. I sense that evolutionary psychologists are really interested in human universals: the famous experiments of Tooby and Cosmides go right to that point. Why are we all afraid of snakes? Why are our babies do hard to toilet train? But they generally don't have a lot to say about variation among humans in these traits.
The other sort that you and I both perceive are interested in human diversity and aren't much concerned with the bigger questions of the ev psych people.
No, they don't "play nice" with each other mostly. It is an exaggeration to say that each regards the phenomena of the other as nuisances. They certainly should see different things: C&T see evolved cheater detection in a logic game while psychologists of the London school see G playing itself out in the diversity of correct answers.
The two areas will come together soon: they are already starting. As some of the comments here indicate, we can't really understand what "Neanderthal intelligence" might mean until we understand the evolution(s) of intelligence. We can examine data all day and still have not an iota of insight about that bigger issue.
Edit: Q&A is now closed. Thanks to everyone for participating, and thanks very much to Harpending and Cochran for their responses.
In response to Kaj's review, Henry Harpending and Gregory Cochran, the authors of the The 10,000 Year Explosion, have agreed to a Q&A session with the Less Wrong community.
If you have any questions for either Harpending or Cochran, please reply to this post with a question addressed to one or both of them. Material for questions might be derived from their blog for the book which includes stories about hunting animals in Africa with an eye towards evolutionary implications (which rose to Jennifer's attention based on Steve Sailer's prior attention).
Please do not kibitz in this Q&A... instead go to the kibitzing area to talk about the Q&A session itself. Eventually, this post will be edited to note that the process has been closed, at which time there should be no new questions.