A lot of the momentum for the new API is continuing, thanks in large part to Romain. A number of new classes have been added, and existing ones have been enhanced. There are more unit tests than ever, and more documentation. We have better build support (with g++ version detection so that we can add some C++0x support where available) and a new examples sub-directory.
We did take one toy away, though. The Doxygen-generated docs were getting so big that we decided to keep them out of the source tarball. (And arguably, they are also too volatile.) We still have the browseable html docs as well as the pdf version (now at over 300 pages!). And we added zip archives of the docs in html, latex, and man format for download.
As always, full details are in the ChangeLog on the Rcpp page. Questions, comments etc: bring them to the rcpp-devel mailing list off the R-Forge page