You can use MEL to assign commands to shelf icons, to make your own hotkeys, and to save most user preferences. You can also customize the Heads Up Display to add your own information.
You can use MAXScript to assign commands to toolbar buttons / icons, menus, QuadMenus and keyboard shortcuts (hotkeys). You could use it to create user preferences by either creating startup scripts or embedding scripts in scene files.
3ds max does not have a dedicated Heads Up Display system, but a similar feature can be easily implemented in MAXScript using so-called ViewRedrawCallbacks and the gw. (Graphics Window) structure of functions for directly drawing and printing text to the graphics device.