Unfortunately (and, to me, inexeplicably), the Group in Logic and the Methodology of Science got dropped from the specialty rankings for mathematical logic in the 204-06 edition of the Philosophical Gourmet Report. But if you are thinking of going to grad school for logic, take it from me: Berekely still belongs in Group 1, where it was last time. The logic faculty in the Mathematics Department is still one of the best (if not the best) in the world. And the faculty members from the Logic Group in Philosophy haven’t changed much from the last iteration of the Gourmet Report either: Branden Fitelson was hired, and John MacFarlane got tenure. True, there are some areas where Berkeley is not as strong as other places (in proof theory, for instance–but Stanford is just across the Bay!). But you really can’t do much better if you are interested in set theory, model theory, recursion theory, or the history of logic. And Berkeley’s philosophy department isn’t bad either, so your general philosophical education won’t suffer.
When I started there, people were fond of pointing out that in the (then) four top-ranked philosophy departments, each one had a Berkeley graduate on the faculty, and they were all graduates of the Logic Group. That’s not true anymore, but still at least a third of schools that are now ranked in the Gourmet Report for mathematical logic have Berkeley graduates on the faculty: Jeremy Avigad at CMU, John Burgess at Princeton, Ken Manders at Pittsburgh, Matt Foreman at UC Irvine (Kai Wehmeier spent a year at Berkeley), Greg Hjorth at UCLA, Peter Koellner at Harvard studied at Berkeley before moving to MIT, Vann McGee and Stephen Yablo at MIT.