Alrighty folks, here they are with preliminary impressions.
In this first picture, the L3000 pad is on the left and the stock is on the right. (Clicky for high res!)
Firstly, there's a fairly notable jump in quality of stitching and construction with the L3000 pads. I'll be more evident in the W1000X pad closeup later on, but the stock pads are almost... lumpy in comparison? And keep in mind, these things have spent a minimum of 40 hours a week on my head, often more if I have a lot of work to take home. I'd estimate they've got over 500 hours on, and those stock pads are about as broken in as they're going to get.
So, what are we replacing? Let's take a look.
The texture IS leather-ish. But pales in comparison. (Clicky for high-res!)
As you can see, it's almost as if the parts they sewed together didn't fit quite right. I've seen one other pair first hand, and had similar impressions. They're comfortable most of the time, but brutal in hot weather and don't breathe particularly well ever. And also, why do they always look very slightly greasy? Check that out. What the heck is that? I wash my hair far more than is healthy for the average human (ask my wife about our shampoo consumption and she'll roll her eyes) and I don't know why that is. Never had that issue with any other pad, pleather or leather.
The pleather pads, without question, are the weakest link (followed really only by packaging) in the otherwise delicious W1000X package.
Much more pebbled, and much better made. (Clicky for high-res!)
So, what do we gain?
Immediately, it's visible how much better the construction is. These WERE intended for $2000+ headphones though that were coated in the finest English leather... so that shouldn't come as a shock. The leather is supple, soft, and appears to cover every surface. Even the bits that stretch and go into the groove and hold the pads onto the phones are the same leather. If you examine the underside, it's a soft suede texture. Cool!
The comfort is top notch now; my ears don't sweat as much and my skin doesn't feel quite as "trapped." I'd imagine this is due to the natural fiber; imagine wearing a Polyester shirt compared to a silk one and you've got the general idea.
Most interestingly, and I didn't really expect this, the sound has actually improved. There's more space around my head now, and detail recovery has improved. It's a general sense of more "air." I imagine this is because we're getting closer to an open design; better airflow simply improves the audio. At this point these feel about as thick as my 6-7 month old W1000x pads did. They're not as padded as the stock pleather, and I'd imagine they'll compact a bit with extended usage. This is a positive: I find the midrange is most influenced and brought forward when the drivers are closer to my ears. Win win.
So, are these worth $100? I think so. I'll have to listen to them a lot over time (poor me) but they seem to have improved my W1000X in both comfort and sound.