There is a keyboard shortcut that makes it easy to split a window and create more panes.

Mouse support can optionally be enabled, allowing e.g. scrolling with the mouse wheel, or switching panes with mouse clicks.

As a tiling window manager, it'll make use of all the space. As you have multiple workspaces and you can resize, etc. you can adjust to see what matters most.

tmux calls the individual shell instances windows. They are displayed like tabs in the status line. These windows can be shared between different sessions, so that any given shell instance can be in any number of tmux sessions used for different purposes or by different users. This allows configurations like the following example: User A: wAB, wA1, wA2; User B: wB1, wAB, wB2

As long as you don't close your session, you may even lose your SSH connection, it'll keep your state just as it was. So you can resume where you left off (via tmux attach).

Tmux is in a state of constant development. Updates are frequent and bug reports usually get an answer within days.