There is one thing I want from my terminal multiplexer: working scroll functionality with Shift+PgUp/PgDn, even in split screens, just like in a plain console, without messing everything up. Is that possible?

You do one better - tmux's mouse mode allows you to scroll with your mouse wheel.

Just add 'set -g mouse on' to your ~/.tmux.conf. You can configure the history size limit by setting 'set-option -g history-limit '. When you scroll the mouse wheel, tmux will enter copy mode and scroll.

The problem is, my terminal already has a concept of scrolling, and its own concept of a buffer, with its own concept of keeping unlimited contents based on available memory, etc.

I've never seen a tmux setup that doesn't fail horribly when these two concepts collide (I can't cmd-f search the buffer for interesting things, I don't get a scroll bar on the right that shows me how far up the buffer I am, scroll acceleration doesn't work, etc.)

Terminal.app already does split panes, tabs, scroll acceleration, search, etc. I don't get persistence, but I don't really understand the workflow where you'd want it. I typically open new tabs exactly because I want a fresh workspace, and I close them exactly because I want to clear my workspace. I can just manually call tmux when I know the thing I'm running should outlast a window (and actually, 99% of the time that's on a server I'm SSH'd into, not on my local machine.)

Can anyone convince me why I need to be all-tmux all-the-time?

Sessions are the killer feature for me. I have a session for each project I work on and can have all my tabs, panes, vim, etc set up and switch between them at any time. Sessions can be persisted so that even if I reboot my machine all my project workspace configurations are saved and ready to go.

How do you persist sessions between reboots?

The session doesn't actually persist between boots. I think what the parent must be referring to is the ability to create tmux session configurations. Then after a reboot if you try to connect to the session which no longer exists the conf will spin it up for you.

Gotcha. I'll have to look up some docs on that, sounds useful.