I compare these headphones to Sennheiser 598SE open headphones and Sennheiser 598C closed headphones. I wanted to find a good pair of open-back headphones with a better mic (derived from a 598C cable) than the one built into my old 598SE that would allow me to sound underwater as long as I didn't hold the mic directly to my mouth. I have relatively large ears and can't stand over-ear headphones or over-ear headphones that are too small. Clamping Force: My first impression of the PC38X is that they clamp more than my old Sennheiser headphones (598C and 598SE). I found my 598SE more comfortable than these, but it's too early to tell. I could put these headphones on top of some books to loosen them up a bit. Ear Comfort: Comes with two sets of ear pads, one is more vinyl and the other is velor. I prefer velor for comfort, don't know how much it affects the sound as I changed the pads almost immediately. Since they are relatively large, my ears occasionally touch the inside of the shell, which could also be due to the pressure mentioned above. I still give my (older) 598SE points for comfort, but that might just be because they're well used and loved. Sound: Improved over my 598SE. I can't compare this to the PC37X which is clearly listed as an improvement on the box. In my experience with open basses the bass isn't overwhelming but I hear it more with these and find it just right. The 598SE was pretty flat, but I like the slightly more bass I got with this PC38X. The soundstage seems a little more extended with them compared to the 598SE, but it's only been 3 days of listening to music all day long so take that with a grain of salt. For example, it sounds like the snare drums are more defined, so I can still feel the improvement. Microphone: The 598SE only has a built-in microphone from a cable I swapped from my 598C, and it's relatively unfussy. What I do like about the PC38X is the boom mic. It auto-mutes when placed vertically, which is great compared to the mute buttons on my Zoom or Slack calls. The biggest advantage for me here is the sound quality, which is mainly due to the microphone part being much closer to the mouth. Now I can hear much better, but while it won't be as good as a dedicated external condenser mic, it's still very good for my purpose and I'm very satisfied. Volume controls: 598Aesthetics: 598SE and 598C headphones. What I have, both are just plain black, which I find pretty classy and understated. However, there's a bit more flair with the PC38X, but it's not as loud as "Look at me, I'm a gamer" with all the RGB lighting in the world. The yellow accents on the outside of the cups and on the microphone are not exaggerated, I'm happy to accept that. I would have liked a different color, but hey, it's not just red or overdone. The cable that comes with the PC38X is black with interlaced yellow inserts, which I think looks nice. However, it's worth noting that the PC38X's cable isn't compatible with the 598SE and 598C, which are interchangeable. The 3.5mm jack on the PC38X is also right angle. Final Thoughts: I really like these headphones and spent about half a week listening to music all day and occasionally playing games with them. I am very happy with my purchase and hope they will last me for many years just like my previous Sennheiser headphones.