[ebroder]

If you have a new enough ssh client, I'd personally recommend setting ControlPersist yes.

This fixes the UI wart where your first ssh connection to a server has to stay open for the duration of all your others (or your others all get forcibly disconnected).

It's not perfect. If the name of a server changes but you already have a control socket, it'll use the socket and connect to the old server. And it also takes it a while to pick up networking changes that break your connectivity, though I've hacked around that with a script I keep running in the background (Linux only, at the moment; requires gir1.2-networkmanager-1.0):

  #!/usr/bin/python
  import os
  from gi.repository import GLib, NMClient
  def active_connections_changed(*args):
      for sock in os.listdir(os.path.expanduser('~/.ssh/sockets')):
          os.unlink(os.path.join(os.path.expanduser('~/.ssh/sockets'), sock))
  c = NMClient.Client.new()
  c.connect('notify::active-connections', active_connections_changed)
  GLib.MainLoop().run()

There's some contention with my coworkers about whether ControlPersist is actually desirable given the tradeoffs, but I personally think it's a huge improvement.