I've also owned a Mesa Baron. Had all the mods done to it. Very versatile and punchy for a tube amp. I ended up wanting it to sound more, well, tubey. To that end going from KT88's to 6550's helped. I ended up listening mostly in Triode. I enjoyed it very much, for a tube amp it could really rock the house, and offered some variety in the ability to vary global feedback, as well as switching from triode to ultralinear as I recall, with a partial option as well. It's not what I'd call a refined or delicate tube sound...it was more like tubes trying to do SS. Still, it was a fun amp and I remember it fondly. Gives off plenty of heat, and expensive to retube with good stuff. Heavy - make sure the seller has original packing if shipping.
Marco