De Lubac is critical but charitable.

“I find no equivalence between his faith and the nihilism of men like Nietzsche or Heidegger. If the filiation of Heidegger to Nietzsche is a matter of history, that of Nietzsche to Kierkegaard is not; and the kinship that can be discovered between these two men of genius should not blind us to their fundamental antithesis. Heidegger no doubt owes much to Kierkegaard, but the debt is not such that Kierkegaard can be held responsible for Heidegger’s nihilism. I shall not look to Kierkegaard for an ontology he never proposed to construct; but it seems futile to attempt to show that, without wishing it and without realizing it, he chose nothingness because he could not choose anything else. To refuse a man the right to inform us of what he thinks and to arrogate to oneself the right to understand him, not as he understands himself but “as he ought to be understood”, is a very subjective principle of exegesis. The principle is not, perhaps, completely false, but it is at least dangerous. It is particularly arbitrary when the thing to be judged is not just a system of concepts but a faith-and a faith that is amply, richly expressed: Whatever the preliminaries may be, should not such a faith be judged first of all in itself? … However that may be, it must be recognized that Kierkegaard is a stimulating writer rather than a safe one. His ideas are not so much a food as a tonic and, taken in too large a dose, they might become a toxin. Anyone who, thinking to follow in his footsteps, entrenched himself forthwith in Kierkegaard’s positions, would run the risk of cutting himself off from all rational life and perhaps from all culture-an inhuman attitude that was certainly not Kierkegaard’s and that would be of no benefit to Christianity in the end” (The Drama of Atheist Humanism, p. 108-109).