Pros: Comfort, good all rounder. Easy to drive, not picky about source or amplification.
Cons: Some will prefer a more subdued design
This was my first real pair of headphones, and they satisfied me for two years. So it is only fitting that my first headphone review be on these awesome headphones. The HD598s are a great entry into personal HIFI. They are not picky about amplification, and will not over analyze bad recordings.
For two years I ran the HD598 from my Asus xonar essence stx sound card. They are a decent enough match, you could do better or worse. I have also tried these on my recently acquired Schiit stack (Bifrost, Asgard 2).
Note: I don't have the poetic vocabulary to do a proper analysis of the headphones, but I can give you a general idea of what to expect.
The mid-range is the star of the show here. They will sound the best with vocals, and acoustic music. The highs are present, but not sparkly. They are not fatiguing at all. The only real problem I had with the HD598s was the bass. It is present, but lacks impact. It is a very enjoyably signature that satisfied me for two years. But alas this is headfi and the itch to upgrade was too strong.
Because of the open design and good sound-stage the HD598s are a great match for Dolby headphone for competitive gaming and movies. You will pinpoint enemies with ease. However, the bass is the weak link here, and lacks immersion. Mad Lust Envy has an excellent write on these headphones in his thread.
The velour earpads, light overall weight, open design, and padded headband all combine for a very comfortable headphone. I doubt anybody will be returning these for comfort issues. You literally forget you have them on after a while.
The Sennheiser HD598s routinely go on sale for ~$150. At this price I consider them a no brainer. They are great entry level can, and the Sennheiser 'Do no harm' sound signature makes for a great all rounder. They bass is still light for my taste, however the pros far outweigh the cons. There is a reason why this is one of the most recommended headphones under $200.