These two amps are really VERY different animals in my opinion: The Herbert has a decidedly "modern" and unique voicing, and also sounds somewhat "produced" right out of the box. It also is the thickest sounding high-gainer I have ever owned. The mid-cut option makes it nearly the perfect rhythm sound for modern metal. To my ears, the JVM has a much more traditional voice, and it's flavor is relies more on that "raw" upper mid presence and signature Marshall crunch. For overall versatility, I might lean in the direction of the JVM. For cleans? probably the Herbert. Gain? Both have much MORE that anyone should ever need, but I find the Herbert to have a smoother, less granular gain structure. Tightness? The Herbert is plenty tight and articulate, while never coming across as stiff or boxy. The JVM may "present" as a bit tighter to the ear based primarily on it's upper mid voicing, it may also "cut through" a bit better in the context of a two guitar band because of this. For sheer "size", the Herbert cannot be beat in my opinion. Leads? Simply a matter of taste on this one, both can do the job very well. Both great amps....But very different. If I could only have one, I would keep the Herbert, most based on the styles of music I tend to gravitate towards playing.
