[RobSis]

I wouldn't call the copy-mode "crippled subset of the real thing".

With tmux's copy-mode, you can even select text without touching your mouse, using e.g. vim-like movements. Which is amazing feature.

The fact, that the copy-mode doesn't jump back down with every change on stdout is also very nice feature.

If you want to work with standard linux clipboard, you still can - just hold shift and select like in almost any linux TUI application.