Meithkiller, in part I was disappointed because I had expected much more than I got (and your review was the basis for my trial!). I'm glad you like them, but they're not my choice.
The plastic is molded in a way that results in the inside of the earpiece hangers and headpiece stopping abruptly without any bevels or finishing at all; they're just cut off at right angles. Sort of like you molded a box and sliced it in half. Over time that means they'll get scuffed, dented, and look pretty bad on the edges. It's cheaper to mold them this way, of course. The plastic has a matte-finish, but without any texture to it, and I don't think it'll hold up at all. Or they'll show their age quickly.
My V-6 cans have the Beyer DT-250 pads. I've already boxed up the 280, but what it felt like to me was that the inside dimensions of the Senn pads left a smaller ear space than the 250 pads (which are better than the original Sonys in every way). Both hit the top of my ears (I am NOT a Vulcan!) but the increased tension on the Senn was something I was not willing to live with. I find the Sony too fatiguing to wear for very long, in part from the sound and in part from the fit.
The Senn pleather is soft, but I bet it doesn't last too long. Looking at my about 15-year-old Sony pads, the composite vinyl & fabric on them is thicker than the Senn's. What really amazed me was the edge finishing of the Senn headpad. There was none. The material is just cut and glued to a clip on for the head pad, and there is another dissimilar material stitched to the pleather on the earpads, to hold them on to the driver cups. The unfinished edges will fray, and once that starts, there's no stopping it. The Sony had every single one of the edges neatly folded and then stitched under, often with a top lock stitch to make a welt that would withstand abrasion far better. But I'm a velour or ultrasuede pad lover.
If I had to define the highs, I'd guess that the Sonys have a peak in the neighborhood of somewhere near 7K Hz, for presence & emphasis; it results in a sibilant hiss or spit, and overall irritating roughness with voice or violins (the Grado SR-80 has a similar peak) that many call revealing and detailed. Well, too mutch etching wears away the substrate... These brand-new Senns had a harsh treble throughout, not with the Sony's peakiness. Sort of like the whole high range abruptly shot up and stayed there.
The depth of the Sony bass is impressive, if a bit exaggerated in the midbass range, and the Senns were brand-new, but they seemed boomy, wooly and uncontrolled by comparison. I felt I was listening to a three-way speaker, not one transducer.
Plasticky? Well, I meant they sounded like cheap headphones, cold and one-dimensional beyond the closed nature of the beast.
Maybe my sample and Jan's were from the same batch, or maybe they represent one end of the production tolerances. Or maybe we represent one end of the production range of human listeners. I just didn't hear anything that made me want to give them more time to grown on me. I have a set of cans I like that others couldn't stand at first listen, but there was enough magic on the first listen I took to make me keep them. But these had nothing.