I watched the video for a while - and it looks almost identical to tmux - basically tmux with different key-mappings. I'd almost guess that the someone has simply gone and skinned the base tmux, everything looks so similar - panes, sessions, windows, resizing, scrollback, etc...

If you already are familiar with tmux, I don't think Byobu will get you anything (based on what I saw of the video).

Yeah, byobu is pretty much an opinionated tmux/screen (you can choose a backend).

Can you elaborate why? I saw most of the video on their website; it looked pretty similar to tmux (with different shortcut keys). Does it have any extra features? Perhaps out-of-the-box session saving even after rebooting?

A couple of obvious reasons: 1) it lowers the bar of entry into Tmux/Screen for newbies; 2) it has fairly intuitive mappings for newbies; 3) it is sanely configurable whilst not requiring the direct use of a dot file (just hit F9); 4) it may be faster to set up than Tmux/Screen (assuming you aren't able to copy a conf file for those); 5) it doesn't require understanding Ctrl-b/a for prefixing most commands.

As a long-time Screen user through PuTTY, I switched to byobu after watching the intro video and it is great.

It inherits and maps Ctrl-a, and makes the transition to using some of the nice new features available in tmux much more accessible.

That's a really nice introductory video they have on the website. The classical music is also a nice touch.

http://byobu.co