I think the thing you're failing to take into account, and what's confusing you, is the different "house sounds" of Schiit and Cavalli. Just because two amps may look the same on paper, doesn't mean they'll sound the same. Schiit amps across the board tend to share some distinguishing characteristics, as do Cavalli amps. What you'll find is that people tend to prefer one sound over the other and they will express their preference as "this is better than that".
So with Schiit amps, you tend to get a more dry, analytical sound with lots of power. This can translate into a bigger soundstage and more apparent detail and space around the notes. When I heard the MJ2 and GMB (with both stock tubes and LSST), it felt like each note was individually presented for my inspection. It was a wonderful insight into the music and appealed to the analytical part of my brain.
With Cavalli amps, you tend to get a more "musical" sound without sacrificing detail. With the Carbon, this translates into a more realistic soundstage presentation at the expense of size. Also, it's a more musical experience where the notes flow into each other, allowing me to fall into the music rather than inspect it. The details are still there, but it becomes more about layering and spacial cues rather than a note by note delineation.
Obviously, I prefer the Cavalli sound as I own two of their amps. I've noticed that my preferences have shifted from a focus on detail at all costs to an appreciation of the gear that will connect me to the music. At first, as I was getting into the hobby, all I wanted to do was inspect the extra detail, hear things I've never heard, etc. Now that I've spent a lot of time in the hobby, I'm remembering that enjoying the music is more important than enjoying the gear.
One of the best setups I ever owned was an HD650+Project Ember+NFB-15 (Wolfson DAC). There were certain songs on that setup that just gave me goosebumps in a way that much of the gear I've had since hasn't. No, it wasn't the most expensive gear, nor was it the most technically superior. But damn if "Great Gig in the Sky" didn't send chills down my spine every time! I moved past that setup looking for "better" gear and it's taken me a while to get back to the point where I'm really enjoying the music like I did on that setup.
I guess the point of my rambling here is that people will listen to music in different ways and that can and will change over time. Is the MJ2 a good amp? Of course, it's just not my kind of amp. Other people love the big soundstage and analytical presentation and that's perfectly fine. Vanilla and Chocolate are both great flavors of ice cream, I just would rather have vanilla if I could only have one today. What flavor do you want?
