http://secushare.psyciumunsqarzsehz5xlgsi2mg4dkvntwf5bwj5kwbcbazwiuhna2ad.onion/comparison
When sent via servers,
basic wire encryption may be in use on the links, but the servers still
receive the files unencrypted. Not talking of the inefficient encoding.
PGP could be applied to XMPP file transfers, too.