I have the K3003 and listen to my brother's EX1000 these days.
I'll specify from the start that I'm very sensitive to high frequencies. I think the AKGs are on another level in terms of detail and they also isolate better, but are more fatiguing. However, the Sonys have a bit more bass, not sure if the level of detail in the lows is better, but they have a bit more bass quantity, and I definitely like that (I'm not a bass head, I have the IE80s and I don't listen to them). They also have a bigger soundstage.
Going from the AKGs to the Sonys is a relaxing experience to these ears. If some find them too bright I suppose it's because of listening to high levels. I personally listen to low levels, I have very sensitive ears, and there's no harshness on EX1000 when listening at reasonable levels. They are very serious IEMs. On the other hand I rarely listen to K3003 without eq-ing the 5.5kHz peak.
Well said, that's how I heard them.
Of course, one man's treble emphasis is another man's treble icicle right in the eardrum.