Counter-cyclic fiscal policy and QE does work, absolutely, but it's likely dependent on size of economy because in most cases austerity works better...but in most cases the economies are much smaller than America's; Ireland, Estonia, Latvia, Lithuania, Italy, Greece (since austerity was forced upon it), HK, Britain could likely've been more austere during the GFC and seen more growth.

Then again although not comparable to America's it's possible that the British economy was/is large enough to sustain even more liberal fiscal policy but given the dependence on import and that it's primarily a service economy I doubt it.

America is truly exceptional.