So it is mosh, but much better? I'll try it.
My big frustration with both Mosh and ET is that neither expose a data communication channel along side the PTY. I use SSH for port forwarding, Tmux paste buffer sync, file transfer, and SSH agent forwarding. Without those features, I'll always need to use SSH/Autossh along side these tools for my other SSH use cases.
What problems are you encountering? It might be worth opening a GitHub issue.
You may be running a distro that doesn't have libsodium (such as ubuntu 14). In this case you have to grab libsodium manually and build et from source.