Great headphones, but not a fan of the earpdads...
As a happy owner of the Koss ESP/950 & E/90, I wanted to try the Massdrop ESP/95X system to see if there were any differences (and to use the other system in my bedroom with my Logitech Squeezebox Touch). While I prefer the all-black look of the original Koss 'stats, I prefer the understated looks of the new energizer. The Massdrop energizer also includes 2 upgrades: sturdier rubber feet and larger holes around the RCA inputs to accommodate larger RCA cables (such as my Bluejeans Belden cables with Canare connectors).
Both headphones sound really good, especially with music that thrives with airy playback, and both energizers sound the same to me as well. While I was never a fan of the stock Koss pleather earpads on the ESP/950, the "velour" earpads of the ESP/95X are somehow worse - they are scratchy and sound worse than the pleather! I tried buying the Dekoni earpads here on Drop, but that order was cancelled. So, I picked the leather and alcantara/leather pads from Fong Audio - wow what an upgrade. I slightly prefer the alcantara/leather to the all-leather earpads, but both are a massive upgrade over the stock Koss and Massdrop earpads (and in my opinion, these earpads actually improve the sound).
Overall, I will continue using my original ESP/950, but now with the improved ESP/95X energizer. The Koss electrostats are so good, I rotate them equally with the Focal Elex, Ether CX and HD800S.