I can't really speak to how my Pass XA30.8 amp compares to other Pass models or any other SS amps for that matter--it is the first SS amp I've ever owned. But I can speak to how it compared to my formerly beloved Shindo GM 70 mono blocks (20 watt SET). It edged them out in my in-home listening audition that lasted over three months. I was turned on to the the XA30.8 by Jack Roberts' review in Dagogo, where, after much consternation that any solid state amp could sound this good, they finally replaced his long time reference WAVAC 300b amps. Mine were demos and supposedly burned in. So when I began the listening comparison I doubted Jack for the first time (he turned me onto to Hi Fidelity cables); I mean they were good, certainly better bass and mid bass authority. But it wasn't until I put another 50 or so hours on them that they began to have the air, depth, and this incredible tonal correctness that made me sit up and say, wait a minute. So back and forth I went, a little incredulous that I was seriously comparing this SS metal beast to my beautiful, glowing GM 70's. I won't bore you with other audiophile terms; suffice to say it got to the point that I much preferred listening to the XA 30.8 on all types of music. Honestly, it was hard to swallow, considering how much musical joy the GM 70's have brought me. Maybe the XA30.8 is special: maybe the more powerful .8 amps wouldn't be able to knock off a world class SET amp. I don't know. Nelson Pass says in the "white paper" included with the amp that each one of the .8's will have different characteristics--and of course different interactions with pre-amps and speakers. But his XA30.8 makes unexpected magic with my Shindo preamp and my Shindo speakers (over 100db sensitivity). They combine the SET type air, delicacy, and presence of the GM70's with unwavering control and tonal exactness that makes it hard for me to imagine there's a more musical amplifier out there for my system.