Ok, so I've been playing my new OVERTONE for about one week, and, first of all, let me say that I'm totally satisfied with this fantastic amp, and with the service I've been getting from Nick.

To begin with, living in Italy, I've never had a chance to try out other Dumble inspired amps, like Two Rocks, etc. so all I'm comparing to is the recorded sound of some tracks I've enjoyed listening to during the years.
The one sound I was looking for in particular was from the track "Revelation", from the Robben Ford album "Talk to Your Daughter". Was I able to get it? In a word YES, and I AM HAPPY

Keep in mind that I'm using a very cheap 1x12 cabinet, made by Epiphone with its stock 70w speaker made by Eminence, the one that is sold with the Valve Junior head. Actually, I'm so satisfied with the sound, that I'm thinking about NOT switching to the famed Celestion G12-65 everybody seems to be talking about. Anyway, maybe in the future, who knows.

What I've been most impressed with, is the fact that it doesn't really soung "like" any other amp, but it seems to have most of the characteristics I've loved in other amps, i.e. the fatness of Fenders, the good "honk" of Voxes (boost on), the dynamics of Hiwatts, etc. It doesn't "sound" like those amps, but it's got those qualities.
It really helps me sound like me, it's really fun and inspiring to play.
What else does one need?
I find it to be a VERY versatile amp. Clean, semi clean, or overdriven. And I've been playing it with a Les Paul, SG, Strat, Teles, Firebird. Another thing is that it sounds good and responsive even with the master on 1 1\2 

I'd like to share my favourite settings so far.
To simplify things, let's divide them into two broad categories:
HUMBUCKERS and SINGLE COILS, and it will be numbers not o'clock references.
It'd be nice to keep it this way for everybody who wants to share.

Anyway here we go, from left to right looking at the control panel:

HUMBUCKERS:
4 DOWN DOWN UP         545 45 35

SINGLE COILS:
5 UP DOWN UP               545 45 35
10 DOWN DOWN DOWN 545 25 35

These settings seem to work well with the clean, boost and overdrive.
Lowering the master to 1 1\2 doesn't really seem to kill the sound and response of the amp. Magic!
Keep in mind that I keep the overdrive trimmer inside the amp slightly lower than it was set at the factory, maybe around 10 o'clock. It makes a big difference in the overdriven tone. It seems to me that the higher it is set, the more Marshall \ less Dumble like the overdriven sound becomes.
I hope it will be helpful, and I'm looking forward to other suggestions.
We've only just begun............... 

Yes, it really does. 
I'm looking forward to your opinion.

I would say so, it really sounds good even at low volumes