Recommendations on good terminal multiplexer [closed]

GNU Screen was invented just for this, it is indispensible and I use it every day.

Also Tmux has been getting a lot of attention lately, it is a lightweight version of screen.

A comprehensive best practice answer covering the management of multiple systems using methods like puppet, cfengine, Spacewalk, Kickstart, and other integral utilities would be appropriate.

Instead, I'll example the benefits of creating your own with:

for H in `hosts`
do
     ssh $H "# do things and stuff ; yum -y update"
done

Thankfully, I've also covered the first one here:

Managing an application across multiple servers, or PXE vs cfEngine/Chef/Puppet

I think Cluster SSH works best in these situations. You get individual windows for each server, but a dialog transmits all of your keystrokes to all servers.

That way, if your 'rpm' command bombs out on one server, you can click on that server and investigate/resolve the issue.

http://sourceforge.net/projects/clusterssh/