Hey I wanted to ask as far as sonic quality do you feel like the Shure 1540 is on par with the TH-600 or better/worse? I know this is also about preferences but I am okay with you deciding based on your preferences. I will be honest this is part of the reason I never bough the Shure 1540 is I never see it get a decent sale, but would love it for a closed headphone that can be used with my dx90 and portable amp. That or the Oppo Pm-3.

The TH600 and SRH1540 are very different. TH600 is very much V-shaped. Boomy, thumping bass and elevated highs with a very recessed mid range. SRH1540 is a much more balanced sound with warmth throughout the range and highs that I find to be smoother to the ear. If you mainly listen to electronic music, maybe the TH600 is the choice, but if you are into a wide range of music, I think the SRH1540 is more versatile. I think a lot of Shure products are underrated and less popular because of the entry cost for new models, but open box, refurb and used prices are generally worth it in my experience. Both the TH600 and SRH1540 are very comfortable to me. TH600 has slightly roomier ear cups.

Thank you for the detailed review! How does SRH1540 hold up after 3 years?
My TH600 is actually gone (one speaker/driver is all the sudden dead!) and these looks great. Especially the better isolation/less leakage, less weight, and better mid range.