I've had a little bit of time on it today, playing through my seven string rather than my main guitar. I have not had the chance to crank it up yet, though, so I don't feel like I know what it really sounds like. (I've noticed that distortion pedals have a tendency to sound pretty good at low volumes but get worse as volume increases, unlike tube amps.)
Caveats aside, my first impressions are very positive. The pedal is articulate, has massive low end, can get the DR sizzle if you want it (or it can be turned off), and is very versatile. So far, running it into fat mode on the clean channel, it really does seem to be like adding a (tightened up, rather than saggy) DR rhythm channel to the Mark V. I think this pedal will be a keeper, and it will allow me to dedicate channel 3 to a Petrucci tone while using this pedal for all out brutal tones.
As I mentioned earlier, I happened to have a Blackstar DistX when I bought the Mark V, though I've since gotten rid of it. I thought the DistX was the best distortion pedal I'd ever played, and that it was better than some high gain amp heads. However, it sounded anemic and thin run into the Mark V clean channel as compared to the Mark V's channel 3 gain. This pedal keeps right up with channel 3, in large part because it has huge amounts of bass.
Still, I am generally skeptical of distortion pedals, so while it seems really great right now, I won't know for sure until I give it more time.
Oh, PS: it can be used as a Muff-style fuzz pedal, and can get Marshall tones as well. I can even get it sounding more like a Mark than a Dual Rec. The crunch/cream, mid, vintage/modern, and boost controls change the character of the pedal pretty dramatically.
