I've moved away from RubyForge and just release through github. There's some barrier to entry there; folks have to follow directions to add github as a gem server so they can install my gems.
But it's so damn easy, and having my code up on github seems so much cleaner and easier that dealing with rubyforge.org.
New gems are auto-built. If there's a problem, I get mail telling me. I can release a new gem by upping the version number. I don't need a special rake or thor or whatever command to release, just git push.