Can't say, I've only owned the HD-25's and not the amperiors. Can say the HD-25's were supremely durable, isolate exceptionally well, are very lightweight/easy to carry. The other side of their isolation is they can start to become uncomfortable after 2-3 hours due to their clamping force. Their sound is very detailed, nice and tight bass. Their mid-high range can be a bit peaky, they can be sibilant and aren't the best for piano music. They are on ear headphones.
The other set I would consider is a pair of Audio Technica ESW9's. They have a bit warmer sound, not as detailed but smoother overall, though not bloated in anyway, great midrange! They do have wood cups. They are on ear and very comfortable. However their isolation isn't as good as the HD-25, clamping force is much less, but again more comfortable. These are great overall cans. They are durable and will last a long time, however I wouldn't be throwing these against a wall, and generally would be trying to take better care of them because of the wood cups.
edit: I am not sure if the ESW9'a leather is real or fake...
You can easily afford both for $500
Edited by arteom - 4/26/13 at 5:33pm