I got a chance to listen to Haitnik's version of "Das Klagende Lied".
Try to locate a copy of another recording of the work that has the "Waldmarchen" movement. The work will become more meaningful if you do. While Haitink's recording is good, the work is almost cut in half without "Waldmarchen".
Wade
I think this is the main flaw of DKL. You have to listen Parts 2 and 3 with Part 1 because of the tonal trajectory and in order to make themes of Parts 2 and 3 acquire a "past" and the consequent emotional charge (in the wagnerian sense). At the same time, listening all 3 Parts together makes the work redundant.
Nevetheless, I still consider DKL "mahlerisch" and I will never set it aside.
Among the complete hybrid version, I recently listened to Hickox's, which I didn't know, and I found it well prepared and recorded, a nice addition to my collection.
Regards,
Luca