I would have thought the ones I had were fake, but the particular pair I had sounded bad right out of the box, then performed normally for a few days before going bad and staying that way.
It's a peculiar issue. They don't make any weird noise or have any signal interruptions, they just sounded like a set of normally functioning pair of mediocre headphones. Anemic low end, but still reproducing all frequencies, extreme midrange scoop, harsh ~4khz spike and low fidelity overall. They also were much louder at a given volume level than they should be when functioning normally.
I'm glad you sent V-MODA your bad pair so they can look into it. When I initially contacted them about it, they were really unfamiliar with such an issue and were dismissive in a sense. Headfi members weren't familiar with this issue either. I sent my defective pair back to Amazon and left a detailed review on Amazon explicitly describing my experience and VMODA contacted me and I tried another pair directly from them. The pair from V-MODA is 100%.
I don't know if this is a new issue, or a few bad units have been circulating for a while going unrecognised. Before I bought the M100s and I was reading about them I observed that some people didn't like the sound and had a completely polarized review and perception of them compared to the majority, they might have been listening a defective unit, but that's just a hunch/suspicion/theory.