Yes, that's great, and it makes things extremely snappy while the socket connection remains open. Sleep your computer overnight, experience some network stormy weather, leave Emacs buffers open for weeks (as one does) and eventually one of those ControlMaster sockets are going to become wedged, and when that happens you're going to go through some things.
If that happens and you don’t want to suffer through the default 30–second (or whatever it is) timeout, then shorten it. Add `ConnectTimeout 5` to your config.
Good idea fine tuning the timeouts. I took your suggestion and dropped the SSH ConnectTimeout to 5, I was still using the default. I also peeked at the Tramp timeouts, and I realized that I had the variable as tramp-connect-timeout and not tramp-connection-timeout. Thanks!
