John,
I bought the Sinopoli-Mahler remasters from HMV-Japan and can report that they are significant improvements over the original issue. But these are not labeled SHM-CD or HQCD and cost me about $45. shipped (the Karajan SHM-CD was around $200). So, sometimes the record companies do get it right.
Over my home system, which is all-tubed except for the Audiomecca digital front end, the sound of the Karajan was unbearable. Even switching out the silver ICs and speaker cables for copper ones did not help. The 4th Symphony was the only one that was even remotely tolerable, but was not an improvement on the original issue. I can still remember the opening of the 5th as being simply painful to listen to.