Believe it or not you're going to find some really biased info against RSA here. If you like the sound of the B52, then that's all that matters to you.
For what it's worth I thought it sounded pretty good. All caveats apply- meet conditions, unfamiliar music (audiophile recording) and source.
edit: good with the HD600. IMO it didn't sound good with the PS-1, bass was very uncontrolled (and loud!)-- my guess is output impedance mismatch?