About Mosh from the Mosh website:
Remote terminal application that allows roaming, supports intermittent connectivity, and provides intelligent local echo and line editing of user keystrokes.
I am loving Mosh so far because I can close lose VPN connection or close my laptop lid and retain my shell session as long as I don't close the terminal window. The local echo is pretty sweet too. No lag!
To get Mosh, going you will need to install it on the remote sever and start a mosh sever using the mosh-sever command. You can then install it on OS X via a package file or my preference, by using homebrew.
brew install mosh will install it locally on the Mac with homebrew.
To connect using Mosh, you can basically use mosh where you would normally type ssh to connect to a server running mosh-server. Some examples of using Mosh can be found here.