Another similar project that aims to do the same thing: https://github.com/elasticdog/transcrypt

The readme contains an itemized comparison, though it sounds some of this actual comparison may be out of date or more specific to git-encrypt (yet another project) git-crypt does appear to use openssl libraries for example.

transcrypt is just a Bash script and does not require compilation

transcrypt uses OpenSSL's symmetric cipher routines rather then implementing its own crypto

transcrypt does not have to remain installed after the initial repository configuration

transcrypt generates a unique salt for each encrypted file

transcrypt uses safety checks to avoid clobbering or duplicating configuration data

transcrypt facilitates setting up additional clones as well as rekeying

transcrypt adds an alias git ls-crypt to list all encrypted files