They're comparable. In wireless mode, it's a toss up for me. Wired mode, that's a different story. The Crossfade 2s kill pretty much all of my headphones when turning off the electronics and putting a wire in; that's how Val designed them, as wired headphones first. the Studio 3, QC35 II, 1000XM2, Solo 3, and B&W PX pretty much all sound the same when going from wireless to wired. Maybe slight improvements here or there. The Crossfade 2s are the only ones that truly take it up a notch. When comparing the Crossfade 2s to the Studio 3s in wireless mode, the Crossfade 2s definitely sound a bit clearer/cleaner, have a bigger soundstage, and get deeper. Sub Bass without question is more noticeable on the Crossfade 2s. The Studio 3s have the mid bass emphasis I like. Just a very punchy, exciting sound. They actually bring out details in certain sounds better. They get louder, and sound better than the Crossfade 2s at higher volumes. Beats to me have always been tuned to listen at higher volumes without causing fatigue or pain. I never listen to my Studio 3s below 11. I usually listen at 11 and I'll sometimes go to 12 if I'm really hyped LOL.
The thing is, on paper the Studio 3s don't beat many headphones. If I ignore the measurements, close my eyes, and crank the volume, the Studio 3s just sound exciting to my ears. I just really enjoy the music and the "Beats" presentation of it. Drums, clicks, and any other sound that brings excitement really stand out coming through the Studio 3s. Most headphones I've tried I couldn't turn up past a certain point, they would either be painful, or muddy/garbled. The Beats line in general are about the only headphones I've tried that I could turn up to max, although I never do, and it remains tolerable. They are designed for a healthy volume. I don't prefer to listen to Beats at low volumes, I have other headphones that do that better. Just my take on it.