OK, now that I've had a full day to make a more complete evaluation I'll give some more opinions.
Firstly, these headphones have really put the pressure on for me to order a record cleaning machine! The detail is so good that every tiny grain of dust is audible. I mean, on the speakers I can tell that a record is dirty because of some surface noise and visible dust, but its actually somewhat overpowering on the 598s. I guess I should also try to keep my 2 golden retrievers out of my room, the amount of shed dog hair in my house is absolutely nuts (and yes I go through a lot of vacuum cleaner bags).
I have really put the phones through their paces though; classical, rock, blues, techno, bluegrass, country... And everything is, as I said in my previous post, a different experience altogether than I've had previously. The imaging and separation is just on a different level from any other headphones I have ever used. I began to notice things in the background noise of some live recordings that I hadn't noticed in the past; like in B.B. King Live in Cook County Jail, in the third track during one of the quieter sections. If you listen closely you can hear a bus or a truck blowing its horn on a nearby road. There are also some interesting things you can here from the inmates.
I did have one problem though, but it turns out it isn't a real problem. When I first put on anything other than a classical record, I kept finding myself having to adjust the tone knobs on every record I put on. Mostly it was because the bass became unbelievably loud when using my Hitachi receiver. I didn't have these problems with my CD player (which has its own headphone out) or my phone, so I assumed it was a hardware issue between my turntable and my receiver. Then I remembered a little button labeled "Loudness." It seems that 1980s Japanese for "loudness" seems to translate to modern English for "bass-boost." Switching it off for the cans fixed my tone balance instantly, but my speakers still sound better with it turned on. I am still playing with the idea of a headphone amp though.
Needless to say, I am quite pleased with them. I can't say what their performance will be like when I get back on the road and use them for movies and Xbox, but I expect it should be at least tolerable. And I will certainly comment on that later, as well as any durability issues. I don't think that will be an issue because they seem fairly robust.
PS: bauzace50, I haven't personally used the 600s, so I can't give much of a comparison. I did however read the spec sheets on both of these and they appear remarkably similar. So close in fact that I couldn't justify an extra $150 for what seems to come down to 1/4 oz of weight, somewhat lower impedance, and 500hz more range at the top end (outside of what is normally considered audible anyway but that's a different debate all together

). I' think you would probably be perfectly happy with the 598s when your 600s finally pack up and to have an extra $150 to spend on some other toy, but only you can decide that. Good news is amazon has a return policy!
Are we there yet? No, never there yet. Keep it rollin', we're paid by the mile.