After reading these few pages, one sort of immediately regrets the loss of the occasionally very high quality material presented, even in the digitally presented, DDI-exclusive editions of Dungeon and Dragon magazines, since they broke the magazines apart and now just post things as individual articles on Wizards' occasionally very difficult-to-navigate and advertisement-laden website. Nevertheless, I do have some thoughts on the Vistani where I briefly compare the 2nd edition/Ravenloft version and the sketchy model presented in Dragon 380. One immediately wonders why the authors didn't spend at least a little bit more time providing any sort of additional background for the Vistani in their context in the Shadowfell, since they felt like they were important enough to the setting to mention at all. I certainly had no idea what Vistani were going in to it, and I imagine that there are probably a good portion of people who, even if they pay for a DDI subscription, won't have read Dragon 380. It seems like a... conspicuous... omission. Perhaps I missed the section on th Vistani entirely in the book, in which case I will consent to wearing the dunce cap at least 4 hours a day for one week.
As it was, I could only gather by the words used to describe them that they were like gypsies that had the ability to travel, seemingly at will, between and throughout the planes, and had at least some small degree of magical power which protects them from serious harm from the more... unsavory sorts of things that they might encounter along their way. The Dragon articles confirmed that they are, in fact, the D&D equivalent of gypsies. However, one of the major differences from the earlier edition Vistani is that in 4th edition, membership is evidently open to all races through a sort of induction process, whereas Vistani in the Ravenloft context seem to have been exclusively human, and the best one could ever come to joining the Vistani was to become a Giogoto, which is to say, someone the Vistani tolerate. All in all, the 4th edition approach to the Vistani seems to take away the magic and mystery of the Ravenloft Vistani a bit, at the expense of making them more interesting, more realistic figures.
In Van RIchten's Guide to the Vistani, one is presented with just about every stereotype about gypsies one can imagine. All of the "negative" stereotypes about Vistani are justified, and all of the "positive" stereotypes are mythologized. There is still a limited amount of this in the 4th edition interpretation: we learn, for instance, that the Vistani swindle people only when it is "fated" that their money should change hands to begin with. A bit of the mysterious fortune teller with untold and limitless magical power details that are so salient in the Ravenloft edition, are softened or flat-out omitted in the 4th edition treatment. In 4th edition, VIstani are a D&D race similar to gypsies; in Ravenloft, they are gypsies, all stereotypes in tact.
In conclusion, briefly, I believe that Dragon 380 will be more of use to utilizing the Vistani in a 4th edition Shadowfell adventure than the entirety of Van Richten's guide would be. It is not to say that there is not anything of interest in Van Richten to add color or flavor to the depiction of the Vistani, but the vision of the Vistani in Ravenloft is too different from the modern type to be of too much use.