Shai, I'm also considering both social psych and marketing PhD programs (though not necessarily specifically JDM, though that's one area of interest). I have found it difficult to get good information on the marketing PhD process, perhaps because there are just so few who go that route compared to the psych PhD. The best forum I know of is the Testmagic PhD Business forum. I have been lurking there for a while and have found it valuable, though occasionally paranoia-inducing. You might get some insight from others if you asked about marketing programs there.
Many people seem to use the UT-Dallas rankings by publication site as a way of ranking business PhD programs (at least as a first approximation).
I agree with womanova on the asymmetry of placement possibilities post-PhD. I assume you are a psych major...? Have you taken any marketing courses yourself, like a consumer behavior course, or have familiarity with business schools? It is sort of a big decision to decide whether you can see yourself teaching business undergrads and MBA students vs. psych students, even if you can do the same research in both places. It's something I haven't been able to quite decide for myself yet. Of course, it's generally acknowledged that the "market" for marketing PhDs is very favorable, and it's unknown to me how much preference is put on a marketing PhD vs. a psych PhD for filling an asst professor of marketing position.
It also appears to me that there is a great emphasis on quant ability/background in the marketing PhD application process (and to a certain extent, in the program itself). Not sure how strong you are in quant but it is my understanding (maybe inaccurate) that what's considered good for psych is not good for business, even in the less obviously math-heavy disciplines. Many marketing programs report median GRE Q scores of 800, and very many of them recommend being in the top 90th percentile in Q to be a competitive applicant, which looks more like econ than psych to me. I've been surprised (almost shocked) by the number of MS Engineering types who are successfully applying for marketing slots in consumer behavior, not just quant marketing. I don't want to make you freaked out about it (though I sort of am at times, heh) but it's something to consider and to look into yourself if you are not blessed with the near-perfect quant score and associated math background.
I hope others can chime in on this subject that is near and dear to my own heart.
(PS Can't help but be amused by the meta quality of discussions of decision-making about Judgment and Decision-Making.)