I used GPGTools before Mountain Lion and was very sad when the update to Mountain Lion broke it, and if I recall correctly it was because Apple more or less totally redid Mail.app and sandboxed it in a way that made it hard to integrate with. Seems like they have sorted this out now, and this should make it for a quicker turn around in the future.
It's been sorted for a while. I've been using it for months, but if you wanted access to it, you had to either pay for it, or build it from source (I want the latter route).
