Hegel, Spectron, Conrad-Johnson

Hi All,
Has anyone ever done a direct comparison between Hegel, Spectron and Conrad-Johnson?

I am driving Infinity 8Kappas. I am considering Hegel H20 or H4SE, Spectron Musician III MK2, or Conrad Johnson MF2550 or Premier 350 (if/when I can find one).

I am looking for a supremely 3D/holographic soundstage, gentle sibilants and strong bass control.
Has anyone hear any of the above amps? Can anyone offer some opinions on them?

Thanks,
Brett