I'd say the FA-003s are closer to the DJ100s in terms of sound signature, but they're still fairly different. What I mean is that the FA-003s are typical of closed headphones, and the HD 598s are typical of open headphones. The Fischers have more bass impact, isolate pretty well, and have a narrower soundstage. The HD 598s don't have quite as much bass impact, and have a wider soundstage. The Sennheisers are the more comfortable of the two, and they're less fatiguing to my ears. There was some spike in the treble area of the FA-003s that bothered me, enough to leave them hanging on my headphone stand while I listened to other, cheaper headphones. Even though the 598s aren't bassier (in terms of impact), they sound a bit warmer and smoother. And they have plenty of bass, just not on the scale of the DJ100s. I find them to be more suitable for general listening. You'd probably be reasonably satisfied with the FA-003s, but I use my headphones pretty much always at home, so I don't have the home/work/closed/open conundrum. I have my open, comfortable soundstagey headphones for movies (the HD 598s, although they're excellent for music, as well), and I've got my closed, bassier headphones for music (the DJ100s). However, I've found myself using the 598s more for everything. I've been burning in the DJ100s, but they just don't sound as natural as the 598s. The Sennheisers are clearly the superior headphones.