My only exposure to Schlippenbach has been through various unofficial live recordings, including the performance of Monk tunes Nate referenced above. The Monk stuf includes Rudi Mahall, who I have really enjoyed hearing on bass clarinet and is overall very good. I have also heard a quartet date with Mahall, Tristan Honsinger and Paul Lovens that was somewhat of a Dolphy tribute and very interesting. With that said, I have enjoyed much less Schlippenbach's slightly more "out" quartet with Evan Parker, Peter Kowald and Lovens.
I would be interested in hearing the trio disc on Enja Nate referenced and the few people I know that have heard Monk's Casino (other than Nate) rated it highly.