There is no "console like experience". Steam's Big Picture mode and a console are two totally different arenas, and I know which arena I personally would rather spend my time in.
I disagree, if limited to games that require control pad input only, and don't exit steam to run another games launcher, the experience is very console like. It breaks down only when third part launchers are required, and the ability to control windows with the controller would get around that problem (not perfectly but in a workable fashion), and in games that require a keyboard and mouse to function, or to be competitive in multiplayer situations. There's little way around that.