Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
The menu bar has always been a kind of "holy grail" of user interface elements for me. It contains all application commands and allows the user to discover the application capabilies and to learn the keyboard shortcuts. Often used commands are placed into the toolbar for faster access.
I did no scientific research about this, but I think first it was Microsoft with Windows Vista which started to put the menu bar into question for some applications:
* The ribbon replaced the traditional menu bar for their office suite.
* The menu bar is hidden per default in the Internet Explorer and the Windows Explorer. To still be able accessing all commands a kind of menu-button has been added to the toolbar.
Until I tried those applications I've been a strong opponent of those "menu bar violations". But after working a while with both approaches it seems that ribbons work very well for applications with a huge number of commands. I think the default setup is quite OK :