felix, just read the TNT articles you refer to.  Are you saying that you wouldn't use a TL431 in new designs?  The measurements Werner Ogiers made seem to suggest that the TL431 is overall significantly better (less noisy) than the LM317 if used properly.

TD - I know that your amp is a high feedback design, however, I'd prefer to use the regulator that has a better measured performance rather than the one that uses the theoretically better system

Michael.