Pros: comfy, closed, sound quality, ergonomics.
I bought these to use in the office at work as my other headphones are Grado SR325is which are open and therefore bleed too much noise.
I spent a lot of time reading reviews and trying to choose between these and the HD25-ii's. I'm very happy with this purchase - they don't sound *quite* as good as the Grado's I have, but they're excellent in every other respect.
The treble isn't quite as crisp on these as the SR325is's, you can't always pick out the detail in high-hats or cymbals as well as the Grados. but in every other respect they sound great, this really is nitpicking.
They're much lighter and easier to wear, the single (much thinner) cable and 3.5mm jack is perfect for use in the office. They stay comfortable for extended wear and fit my small head perfectly :)
The carry case provided is ideal for packing them into and taking them home each night (no way I'd leave these in the office overnight!).
I mostly drive these from an iPhone 4S so they're ideal having a 3.5mm jack and a nice thin cable. I don't really think they need an amp, comparing the sound straight from the iPhone 4S with them being driven by an Aune MKii, digitally fed over coax from a RealTek 888 and iTunes playing lossless audio - the difference is tiny, if any. Having said that, I have got a Fiio E17 on order so I'll do further testing then...
Highly recommended pair of closed cans, perfect for the office, seem to be easily driven and with enough quality to really let you get immersed in the music.