It's clear to me that Sartre owes his reputation to his ability to prostitute himself to the PCF party line.
His job was to take the stale Marxist-Leninist dialectic that the French had wearied of by the 1930s and to recast it into the fashionable jargon of the 1940s and 1950s - he was an ad exec for the PCF, not a serious thinker.
Foucault actually came up with some interesting ideas - importing Nietzsche into sociology. Ultimately a fruitless endeavor, given the low quality of Nietzsche's original "insights" but something new, in any case.
Levinas was a much more intelligent and innovative philosopher than either of these, and of course, there are no news articles lamenting the neglect of Maritain, Marcel or de Lubac.
But for anyone to get an idea of how contemptible Sartre's intellectual abilities were, one merely has to compare Camus' Le Mythe de Sisyphe to Sartre's Existentialisme et Humanisme - read in sequence, one becomes aware of what a lightweight Sartre was.
Camus was a terrific writer, as was Malraux. I'm not familiar with Levinas' works. Which of his books would you suggest for a first-time reader?
Nietzsche at least faced up to what nihilism meant for the future of humanity. The incoherent Nietzschean Marxism of Foucault doesn't. It's the Disneyland version of Nietzsche. It assures us that all will be well once the Last Man achieves sexual satisfaction.
Of course, vulgar Marxism is true Marxism. Non-vulgar Marxism has merely appropriated the concern for culture to further the great cause of liberation, which now evidently means the self-satisfaction of the Last Man.