Over the past 30+ years I have owned a number of Sennheiser headphone models, including the 598, 600, 650, and currently the HD700. Each model has excellent audio qualities, but when cost is factored into the equation I believe the HD700 is the best value. Several online sellers currently offer the 700's for $450, which makes them a screaming deal.
I have the 598s and seldom use them that much these days. That being said, when I have used them, the soundstage has been engaging, mids warm and comfort unparalleled!
I used the 558 for 2 years and loved it. Then I got the 600 through Massdrop for an unbeatable price and it is outstanding! Clear sound good soundstage, real impact to the bass (natural, not basshead sound). This is a must have. You do need an amp to get the best from these. I use the Aune T1 which has been sold by Massdrop.