Tony, to answer your questions: the c't folks found that the Fraunhofer dampens high frequencies more than Xing and LAME, but also produces less pre-echo. They didn't specify a "magic" bitrate where artefacts disappear.

As the article is in the current issue, it's not yet online. They may or may not put it on their web site (only some selected articles make it to the Internet). Theis URL is http://www.heise.de

Daniel