I listened to the AKG 3003, comparing it to the Sennheiser IE 800, HD800, and HD700. Driven by HDVD800 with DAC input.
Sound:
AKG3003: Bass ok, not as deep and powerful as IE800 but ok. Mids are more pronounced (like HD800), on some recordings a bit too much resulting in a shouty sound, not as natural and smooth as IE800. Treble: BIG BIG trouble. Awful sibilance and not good at all. General impressions: a bit incoherent, probably due to 3-way drivers and phase incoherence. Mids/treble sound a bit "hard" and compressed. Bass more dynamic.
IE800: bass is really deep, but not bloated in the mid bass. Impressive depth brings sound to a new level. More impressive than the Stax 007 in bass department. On some recordings such as pop/electronica, bass might be too much, but this is very recording dependent. Mids: perfect classical sennheiser sound, compared to 3003 or Stax lambda series, the mids are a bit recessed, but to my ears sound more realistic and does not result in listening fatigue. Treble: initially a bit sibilant, however after 200 hrs of burn in the treble is really nice. Also like the bass, the amount of treble is very recording dependent. Tried tea bags but it flattened the sound across the whole freq range.
HD800: Weak bass, nice mids, too much treble. Result. Anemic sound, not very exciting to listen to.
HD700: A bit more V-shaped than HD800, more fun, but not up to the level of IE800.
Winner: IE800 by a wide margin. IMO.To my ears that is!
The AKG3003 is heavily over-priced.