Either you get Gadamer or you don't. Either you understand/respect/follow him out of the Heideggerian 'Clearing' or you start hacking therough the dense and tangled undergrowth and make your own path. I've never felt much affinity for his magnum opus, 'Truth and Method,' but then, all of Heidegger's belabored philosophical children leave me a tad cold... Hannah, Karl, Hans... The only one I felt had something new to say was Levinas. So let's just say that, 'ideologically' I'm not an enemy- just a contender.
You buy this- you get jargon juggling. Lots of jargon juggling. Little substance. I wonder what Celan would have made of this, as he too was very influenced by H's opus, Being and Time, he kept an annotated copy with him. This 'engagement,' as it is described, is another shred of soulless, brittle, and all-too obscurantist work that drains the lifeblood of Celan, page by page. The essay, "Who Am I and Who Are You?" Didn't seem to get anywhere on that topic. Endlessly tangential. Painfully dry.
It's strikes me as odd that Celan seemd able to draw upon Heidegger more deeply and interestingly than Lowith, Gadamer, et al... Most academic reformulation, elaborations of the H-ian legacy come off as tendentious posturing- weilding academic lingo as a blunt plank with which one beats one's readers into unconsciousness.
Beware. Get the Felstiner work, if anything. Or better yet... Let Celan speak for himself.