GPG works fine. It's difficult to get people to use encryption regardless of the implementation... I used to work for an organization that required, by written policy, all email to be encrypted. Everyone had an S/MIME cert with a short pin... the number of encrypted emails I received over a 7 year period was precisely - without exaggeration - '2.' People do not care about encrypted email, and don't want to bother with even the slightest inconvenience. This is by far the largest problem with encryption, much more so than any 'it's too difficult to use' excuse.