i have both the ath-es7 and the klipsch image s4. what the other have said above is pretty much true. i listen to a lot of electronic music: mostly downtempo, trip hop, indie electro, etc. the s4's have more bass, but i definitely prefer the sound of the es7's. they still have a good amount of bass, and it is cleaner and less muddy.
one main difference really (as others have mentioned) is the COMFORT. other than the fact that one is an iem and one is supra-aural, the klipsch really spoil your ears as far as comfort. for me the es7 are fine for like the first hour, then my upper ear starts to get a bit sore after that. i still reach for the es7's more often though these days. when they start to hurt, i just take a break or bear with it.
i don't have the most discerning ears, but i'd say the es7 have bigger soundstage, a little bit cleaner sound, but a little less isolation. the es7's amaze me with how little they leak though! sound will creep in, but hardly any will escape if they are on properly. i blast them on the train and no one around me gets annoyed.