It's a Dumble..... what more needs to be said!
It rates right along side a Trainwreck. Both amps were built in limited numbers (not production) and for players interested in having an amp voiced to suite their particular playing style.
Both Howard Dumble and Ken Fischer built custom amps that were tweaked with no two exactly alike. Not to mention these guys only built a hand full of amps in any year.
You can't even begin to compare these amps to any production amp or even some of the better boutique amps available. You may get close by having one of the many custom amp builders build you an amp.
There are a couple of guys building Dumble clones like Brown Note Amps: http://www.brownnote.net/
or Bludotone amps: http://www.bludotone.com/
both of these guys will custom voice a build to suite the customer and have great reputations for providing unmatched quality in a custom amp.
Want a Trainwreck clone..... check out Paul Ruby or you could buy a limited build Komet.
There are a couple of companies who build quality amps that have simular charicitistics like Two Rock, Fuchs, Bruno, Dr Z, and others.
But if you're looking for that "chunka chunka chunka" buzzsaw saturation.... stick with your Mesa Engineering (Boogie to us old timers), a Bogner Uberschall or a Fuchs Frost 100. These amps (Dumble or Trainwreck type) won't suite you at all.
Want a amp that will bring out the best (or worst) in your playing (very touch sensitive and capable of being controlled by your guitar volume knob) find something based off either a Dumble or Trainwreck.
There is a reason why players like Eric Johnson, Carlos Santana, Larry Carlton, Robin Ford, Joe Bonamassa, along with a long list of other players recognized for excellent tone, either have used or had amps made based on the Dumble or Trainwreck tone circuitry.
Most players don't realize it, but the key to great tone is influenced by your amp far more than guitar or pickup. Don't get me wrong those count too! But like someone pointed out in an amp thread recently.... "a $10 000 PRS Private Stock will sound just like a 15 watt solid state amp if that's what you plug it into!"