I replaced the stock pads on my K7XX with the Elite Hybrid pads. I have three points to cover: look, feel, and sound.
They look a lot cleaner than the stock pads. I will also note here that the build quality is good.
They are slightly more comfortable for two reasons. First, they increase the distance from the drivers, which means my ears are no longer touching the foam. Second, they have more give than the stock pads, which is nice for wearing glasses.
Finally, after swapping back and forth, I do not notice a change in sound beyond a subtle decrease in volume. (Maybe if I were to have one of each pad on while listening to a song that was playing in mono, and I were to change the output to all L or all R, then I might notice a difference...) However, the sound component of the listening experience is significantly improved due to the memory foam in the Dekoni pads. I find the K7XX to be a very creaky pair of headphones, and the rigidity of the stock pads accentuates this creakiness. By contrast, the Elite Hybrids (and presumably the other Dekoni models) eliminate these annoying sounds emanating from the headset.
If you wear glasses, then I would caution against an all leather model because I find that glasses rub against the leather, which can create very loud vibrations with the slightest movement of the head. This is my experience with my ZMF phones, which have (extremely comfortable) all-leather pads.