I am getting crisp, full bodied, rich sound on all genres from classic rock to western classical, jazz to Indian classical, gamelan to Techno, western country to Celtic. If you want to try something that has the potential to burn your ears, try Ram Narayan playing sarangi.
So I can only say that it took a very long time for my Delos to settle in. I was so irritated after the first two weeks that I contacted the distributor and manufacturer. From my description of the sound and my setup they agreed to letting me return it for an inspection. I came very close to doing that.
I listened to a record last night that is far harder to get right than Led Zep. It is Bruch's Scottish Fantasia with David Oistrakh and the London Symphony, CS 6337 Blueback. That recording has very high screech potential. It sounded fabulous through the Delos. Followed that up with Spam Allstars (high energy techno-jazz with Pee Wee Ellis); then Travis Tritt (country / southern rock). Got a lot of pleasure listening through the Delos.
I should mention that I added a K&K Lundahl 1941 SUT when I got the Delos. So I am not sure which of the pieces was having the break in problem. Could be that they both were.
In any case, if you have less than 100 hours on the Delos, you may want to stick with it a while longer.