I purchased these trying to find a pair of 'entry level' over-ear headphones that were closed so I could listen to music with other people around without annoying them with an open design or annoying myself with something that wasn't sealed. Comfort was also an extremely high priority for me, as many headphones give me tension headaches or migraines. I was pleased with my ATH-EW9's, so instead of taking a gamble on a brand I hadn't heard before, I went with AT again.
 
These headphones definitely took some burning in to get to a fuller sound, but hit a sweet spot fairly quickly without any equalizer fiddling. They filled the gap that my ATH-EW9's didn't cover - "prog" rock and pretty much any music with heavily distorted guitars. They handle music like The Mars Volta and The Red Hot Chilli Peppers beautifully, giving definition to each layer of production. Vocal acoustic sounds clear and warm. Where they're a bit lacking is hip-hop or hip-hop derived electro. More minimalist electro (think Bjork) sounds clear as a bell, but they get a little lost trying to navigate heavy bass lines.
 
If you're a bass addict, I wouldn't recommend these. I personally dislike the "bass blaster" sound common to brands like Sony and Bose, as I feel it compromises the rest of the music. 
 
Otherwise, they're wonderful headphones especially if you have comfort issues.