Well, now that I've had a couple weeks with this pickup, I figured I'd share some of my official thoughts on it. If this is in the wrong section, I apologize. The pickup section said something about waiting 3 months and well, the restless masses demand another DS7 review! If this gets deleted, no biggie

Anyways, on to business...
The Guitar: Ibanez K7 FB, mahogany body
The Rig: Mesa/Boogie Triaxis/2:90 w/ TC Electronic G Major--> Mesa 4x12
Orientation: Solid bar towards the bridge
Tone:
After initially being slightly underwhelmed with the tone, I soon realized I had some duds strings on there. When I switched to different strings (Ernie Ball 10s),
everything changed and I've been in heaven ever since.
I've tried almost every pickup DiMarzio, Seymour Duncan and EMG makes, and I think I've been looking for this pickup all my life. It just seems to have a unique quality of heaviness that has to be heard to be believed. It has an incredible crunch, with all the attack and bite you could ever want, but still sounding heavy and complex, not sterile. It has a lot of low end, but is very clear and warm, not muddy at all. It's middy but it doesn't honk, it's not like a Blaze Custom or a Tone Zone, it has just the right amount of mids to sound mean and in your face, but not over the top. It has all the articulation and treble you'd want, but it's not harsh or too bright.
In the past, pickups have done one of these things as well, but didn't have the whole package like this does. There's just not one aspect of this pickup that doesn't sound perfect. If you're shredding, playing blistering fast virtuoso leads, intricate rhythm riffs, or just doomy single note licks, it seems perfectly suited for all of that. I feel like this pickup should replace the Blaze as THE 7-string pickup people seem to goto by default. It just has everything the Blaze has, but with infinitely better articulation and punch. Power chords are still just as warm and heavy, it's just not quite as scooped.
I should also note that, even at near-defeaning volumes capable of playing stadiums with, there is absolute ZERO noise or hum, even with the volume knob maxed out, as long as you have some kind of noise-gate engaged (which goes for really any high-gain tube amp situation). No feedback, no hum, nothing. Dead silent. I can stand right next to the speakers and hear really nothing, yet if I hit a note on my amp I'd be thrown back at the wall ala Marty from Back to the Future. With 0 noise suppression, there is bit of faint hum if you aim your guitar up to an electrical outlet or something, but I've yet to encounter any situation, either at home or live at stadium volumes, where I hear a damn thing. The bottom line is, a certain pal of mine will argue to the death that this is a noisy pickup, and I will goto the grave saying the opposite.
This is just the best pickup ever. In the right guitar, I still love many of the 7-string pickups out there, such as the DiMarzio Blaze/PAF/Evo/JP7/Air Norton and the Duncan JB/Custom/Invader. The EMG 707 can be cool too. All around though, the D Sonic just has given me the best all around experience of any pickup I've ever heard. Lead tones, rhythm riffing, deep rich low notes that growl like a monster, singing harmonics and terrific bite, everything you could want this delivers. It's like the PAF7 in a way, but way more powerful (especially in the lead department, rhythm is kind of similar).
Granted, perhaps with other rigs or guitars with different tonal properties, this pickup might not be as cool, who knows. But, if I had to have one guitar with one pickup, I would not even hesitate to choose the D Sonic.