Got the two hooked up today and I am very happy. The amp arrived in perfect condition and married to the new Ampeg PF115HE 15" cab, it sounds great. I didn't always believe you could hear the difference between SS and tube amps, but I believe I can easily discern it in this rig. The real difference I notice with the MM head is the richness of the bass tonality and, interestingly, the speaker seems to be able to handle more volume with less effort/degradation of the sound. The speaker performs better with this amp than with the SS Mesa. The overall sound of the amp is clear and clean at lower volumes. When my wife isn't around I'll crank it and see what happens! She gets rattled when i do that.
I really like the simplicity of the controls. I've never been all that found of 6 knob EQ systems, more hassle than they are worth IMHO. The difference between the "Normal-Bright" and "Normal-Deep" switches is striking and really a nice feature. I can go from really deep and thumpy to crispy and edgy with the flip of one or two switches.
My next experiments will involve playing with variations in the master vs. channel volume controls and mid-treble differences.
Thus far, the sound, power and tone of the amp-speaker combo is just what I had hoped for. We'll see how things sound at our next practice with 2 15" cabs and some real volume. A good report!