That was the slogan of OS/2 2.0. But by then where Windows 3.x was already out and in 386 Enhanced Mode, more than good enough. It also had the extra "escape hatch" of being able to quit to real DOS if a DOS box didn't work.

OS/2 1.x's DOS box was bad, with lots of limitations, which isn't good when most existing PC apps are DOS apps. As for GUI, well, lets call the Presentation Manager 1.x v Windows 2.x a no-score draw.