This review is for the Jerzee version installed on my Sennheiser PC38x. First off, these pads are very comfortable, and they alleviate the heat generated by the Midnight version of these. They are thicker than stock pads so they will push the drivers a bit further out from your ears, and thus they seem to produce ever so slightly more soundstage at the cost of a little detail. The worst part is that my PC38x sounded a bit darker compared to stock pads, but it wasn't anything that couldn't be corrected with some EQ. Overall, these are good solid pads, but honestly, they aren't a great improvement over stock pads to warrant the cost in my humble opinion. If your stock pads are worn out (as Sennheiser pads often go) these will definitely be a solid replacement with a slightly different spin on the sound in a good way.
The Earpadz didn't change the sound of my HD-280s very much but they definitely changed the comfort level. For long term wearing sessions my head doesn't get as sticky with the earpadz and they just generally feel more comfortable.