Pros: Smooths my older, rougher recordings.
Cons: Makes all my music sound like it's been recorded in the same venue, on the same day.
For relaxing with a nice glass of wine while reading a good book, the wash of music from the HD598 is very soothing.
Sadly, its mid bass bloom makes my delicate lute music sound like guitars. In fact, everything seems to have the same over-weighty mid-tone about it, however it was recorded. Deep and full, politely sweet but never exciting. It's as if my CDs are camouflaged in a Sennheiser soundscape, with a feeling that there was a Sennheiser engineer present at every recording session, insisting on the exact same feel, no matter whether the music was classical, rock or jazz.