I really have a liking to these headphones...HD 598
The Senn 5XX have always had a reputation of being bland and boring and my HD555 certainly have that look. But the tacky look of the HD598 really appeals to me ;-)
The Boring & Bland HD555
The posts I have been reading about the HD 598 are by in large very positive. But as I recently purchased a set of HD 650 I will not tempt myself to listen to the HD598. In fact as a result I have been listening to my HD 555 again and they are great value fones. I have been enjoying the lightness and comfortability of the phones and the single cord. A great new feature of the 518/558/598 series is that you can replace the cord with something shorter for more portable listening. The HD650 are heavy & sacrifice some speed for that extra bass & detail. I have heard the HD 598 have a great soundstage. Recently I have just been using a set of Yamaha YST M8 for my headphone amp and it is surprisingly quite good (although lacks bass of a dedicated headphone amp). So I am entering a new phase of thought on headphone amping.