Jazzmeup, I would believe that you would find the Pass Labs 350.5 to have a "warmth/liquidity" that the Classe and Plinuis do not have.
All the above stated amps are quick, detailed, and smooth, but the 350.5 has what alot of audiophiles would call a tube-like signature were timbres and images sound more like the real thing.
I went from a Edge NL-10 to the 350.5 because of this special quality and did not lose any dynamics, details, or extension at all. They are all fine amps, but the new .5 series of Pass Labs are real killers sonicly.