TL;DR
I'm blown away by the sound quality and detail for the price. Keep the stock pads and add a Bellari SE560 for a versatile rig.
Sound Quality
Tight bass and midbass (although recessed - it's there, and you can EQ the response very nicely)
Smooth neutral mids
Very little sound coloring
Amazing imaging and detail
Defined highs without being tinny or fatiguing
Comfortable cans on my dome
Comparisons
Comparing them to other headphones that I have tried and like;
They have much more detail and a better soundstage than the Monoprice M1060 (current generation). The M1060 has punchier bass. I also find that planars make a lot of sounds seem compressed to me, which I don't like.
Sennheiser/Drop 6XX are better out of the box for listening to EDM, but for everything else, these guys rule. Also, I prefer the stronger clamping force of the 6XX.
Pads
I have the Drop OE pads, the Koss OE pads (ordered from Koss's website for $5...) and the Dekoni pads.
Drop OE pads - some have said they feel cheap and they don't like the foam. I don't mind them at all. They don't feel luxurious, but I don't notice them once the music starts.
Koss OE pads - slightly more comfortable than drop OE, but don't do any favors for the sound. Basically it sounded more muffled... with no advantages. They went in the trash.
Dekoni pads - much more comfortable than OE, concentrates sound stage towards front, gives a nice, restrained bass boost. If you are looking for a colored sound response, Dekoni will give you that although at the expense of some clarity.
For a serious, inexpensive level-up
I recently added a Bellari SE560 into the signal chain. It's a nice compact sonic exciter with a bypass button. I think it adds three major advantages to these cans:
If you want a colored sound, you can dial it in on the Bellari, while maintaining all of the clarity and detail that the cans are capable of
You can use the Bellari's volume knob if you don't want to mess with the strangely designed "acoustic level" knobs on the OE energizer
Bellari has a bypass switch, so you can go from "accurate, revealing, balanced" cans to "fun, colored, personality" cans with the press of a button. It's the best of both worlds!
Negatives
As others have mentioned:
If dust gets in them, there is a buzzing sound. I have not experienced this but others have.
Volume knob is stupid.
Build quality is fairly flimsy, but I am not worried about them falling apart.
Comparisons Comparing them to other headphones that I have tried and like;
Pads I have the Drop OE pads, the Koss OE pads (ordered from Koss's website for $5...) and the Dekoni pads. Drop OE pads - some have said they feel cheap and they don't like the foam. I don't mind them at all. They don't feel luxurious, but I don't notice them once the music starts. Koss OE pads - slightly more comfortable than drop OE, but don't do any favors for the sound. Basically it sounded more muffled... with no advantages. They went in the trash. Dekoni pads - much more comfortable than OE, concentrates sound stage towards front, gives a nice, restrained bass boost. If you are looking for a colored sound response, Dekoni will give you that although at the expense of some clarity. For a serious, inexpensive level-up I recently added a Bellari SE560 into the signal chain. It's a nice compact sonic exciter with a bypass button. I think it adds three major advantages to these cans:
Negatives As others have mentioned: