Searched around and couldn't find a thread that fully satisfied my specific question... so here goes: I currently own a Mesa Fathom (now known as the M6). An opportunity has come up with a fellow on Craig's List to swap my Fathom and $260 for his Mesa/Boogie 400+. The Fathom is class D solid state with one preamp tube and the 400+ is 300W all tube. I'm really quite happy with the Fathom, but any time I play a gig where there's an all-tube back line amp, I just love the way the tubes play/feel. I like a little bit of warm grit in my tone and can mostly achieve that on the solid state with my collection of pedals (darkglass b7k and vintage microtubes, empress comp, etc.). Can the Mesa 400+ get close to an Ampeg growl? I own an Ampeg 8x10 and a Mesa 2x10. I'm not overly concerned about weight of the head as I may pick up a little Aguilar amp sometime down the line to use for small gigs with the 2x10. I believe the 400+ Is only about 10lbs heavier than the Fathom anyways. I was looking for some input as to whether it'd be wise to make the trade. The Fathom is newer technology (and goes for more money new than the 400+) and I like a few features about it better, but wanted to ensure that I'm making the right choice in switching to the all-tube. Is this a "if it ain't broken—don't fix it" situation or do you think I'll never look back once I go all tube? I would love to own an Ampeg SVT-CL to match my cab some day, but for now was mostly looking for input on the MESA opportunity.