Aside from being heavy and a little short on power, it's a great amp! My first "professional" amp was an SVT-III just like yours. I foolishly sold it when I wasn't getting enough volume with my little Goliath Jr II cab.

Turns out that the gain-stage tube was a low-gain tube, but I only realized that later in life after I learned more about it and about the various kinds of 12a_7 tubes and tube gain. I'd have traded a little noise for more gain, I think... Or maybe not.
I gigged it with a Dietz 2-15 down in Austin a few times about 12 years ago and it was quintessential "rock and roll" with my then-newly-built Warmoth Jazz (which I still own). I had that amp from about 1996 to ~2000 or so.
If I found another for a price I could justify (being that it would more or less sit at home as a practice amp), I might pick it up.