sorry to spoil the party, but i didn't think much of them. Get a pair of Equation Audio RP21's instead. Cheaper, and better than the Sony's. if you can get your hands on a pair of Sennheiser HD25-1's you'll be better off.
as for the 595's, they'll be a touch better on the detail, and tighter on the bass, but there might not be as heavy on the bass. but that's a good price for the HD595's. if you're looking for a bit more detail, then get a pair of Alessandro MS-1's.
personally the price of the Equation audios have dropped rapidly in the last few months. Mine cost £75 plus p&p from the states, so they ended up being very expensive, but they are great, far better than the (now) £45 or so price tag suggests. try everyones friendly bidding site for the
RP21's.
but for comfort, the only headphones i found to beat the HD595's are the Denon AH-D1000's. but keep your eyes peeled because the new Denon AH-D301 and D501's are coming out soon. 301, should retail at around £39 and the 501's £59.