That lead tone he gets into around 6:20 is something really amazing about the Paul. I don't know how well people can pick up on it from the video, but when you play it, it's a real lively 3D kind of lead tone. It's quite unique and there are really not many amps which can do that kind of thing at high gain. In a way, I think it kind of either refines or redefines the liquid lead tone Diezels are known for.
It records extremely well and has that cut factor which always seems to sit right in a mix. The clean tone speaks for itself. I think it's clearly in the top echelon of immaculate cleans and breakup. Honestly, the on-board digital reverb was kind of a question for me before I got it, but it's not kind of synthetic like something you would get in a Marshall JVM or something. It's not a real strong reverb either and kind of reminds me of the reverb on a Marshall DSL. It's quite natural sounding, adds just enough depth and dimension to make good use of the reverb without drowning anything out. Bottom line, it's a reverb that serves only so far as being extremely useful rather than creating dramatic effect.
It's about time a good humbucker demo was done too because a lot of emphasis has been placed on the single-coil tones which have already been proven to be amazing, but the Paul really shows it's true diversity through humbuckers because this is one of the very few amps which marries authentic classic tone with high gain. I think it's about 95% as brutal as the DMoll, VH4, Herbert, etc...
I've noticed that will alnico and hemp cone speakers, the Paul's 3D characteristics are accentuated. In fact, there have been a few times when I had to check and see if my effects processor was on. Not that it's a high gain processed kind of sound you might get from say an EVH 5150 III (which I like too by the way), just that it's surprising how alive the tone becomes with those kinds of speakers. Celestion Gold, Jensen Jet Blackbird, or Eminence Red Fang would be great speaker choices in my opinion. In fact, the speaker which I recently bought for my Paul is the Celestion G12H30. I really like this speaker with the Paul because it lets you run the treble+presenece+mids higher but lets the Paul keep it's classic edge without becoming harsh. That particular emphasis in EQ seems to lend the Paul to more Marshallesque upper mids I think.
I can't honestly criticize the Paul in any way, shape or form. I WISH it had the mid scoop functionality of the D-Moll because I think that part of the D-Moll is the best mid function of any amp I've played aside from the Engl Morse. It's a fantastic feature and a great selling point of the D-Moll. If the Paul had it, then that would be awesome. However, it's just a wish. If I had the money and Diezel had the willingness to make the mod, I'd do it, but it would be a hard choice between it and the reverb.
I'm surprised that this amp hasn't taken the amp world by storm yet, but if good demos keep popping up, then people might start catching on.