My issue is that I have a build server, which with the old portage repository, I synced the build server and build the packages, when all has been built, then I can sync the portage to my local portage-repository and then I do sync all my other machines against the local portage-repository (this way they never will get a portage which hasn't yet been built) and then run an emerge world to get the binary packages installed.

The new kits seems to make this more complicated and it would be nice to have a documentation written so people could have a good build server setup.