They really are special, because Alvarez ws special. Listening to him, it was like he was the steve fryette of Marshall. He understood how to use the design and alot of people could have benefitted from just listening to the guy talk about the amp he designed.
They also sound incredible with the master cranked on up and channel volume brought in for taste
I'll take a JVM410 over a diezel ANYTHING. I felt like it smoked the herbert mkiii in the room also. But.. so did my SLX. The JVM and SLX are my 2 favorite marshalls with the DSL coming right in a close 3rd.
If you can't get a variety of extremely amazing tones from plexi to all out Jose mod and beyond out of a JVM410, we can conclude it's user error at this point.