There are a lot of alternatives in this space (I wrote transcrypt [1] for just this purpose), but I think the killer features here are that you don't need shared credentials since you can have multiple keys, and that it's generic enough to work with multiple VCS's.
With transcrypt, I do the encryption/decryption transparently once a repository has been configured by utilizing Git's clean/smudge filters, but it uses OpenSSL out of the box rather than GPG. A different workflow, and there are certainly pros and cons to both ways.