I use a Mini-Brute IV. Not the newest version with the "sonic circuit," but the model before that (like this one, though $1,008.31 seems a tad steep:
https://reverb.com/item/7011077-polytone-mini-brute-iv-used ). In general I like it. It's about as small as an amp with a 15" speaker can get. It has done well at projecting my godawful screeching noises toward the two or three people unfortunate enough to be at my concerts. When it comes to conventional guitar playing, it definitely steers one toward full fat roundness--I've never been able to get anything "chimey" or "sparkling" out of it, and sometimes it can be downright muddy. But there's a fair amount of tweakability there, with the treble switch, EQ, and overdrive channel, and it's possible I just haven't hit upon the right settings. There's also the effects loop, which is parallel. It seems like even with the FX loop gain maxed you still get your clean sound mixed in.
Most of the time lately the pedals going into it have been: Behringer Filter Machine > FreqOut > Canyon, and sometimes a Count to 5. I've had somewhat questionable results with fuzzes. They've had a tendency to sound somewhat brittle. But not disastrously bad. Regarding the onboard effects, I think the reverb is totally decent, and the overdrive is not the worst example of its kind (and at low gain it's pretty much clean and has a different character than the clean channel).
I see that people use these for bass, and while the amp can handle low pitches, I've found that it can get farty if you play too loud. The cabinet is totally unvented, so if you play bass through it you may notice tremendous gusts of wind jetting out via the jacks.
So that's the Polytone Mini-Brute IV, 1990s? early 2000s? vintage. Just one of the baffling array of Polytone variations.