I just came back from Stereo trying various monitors (UE900, AK3003i, IE800... on top of my on-the-go W4). I have to say the IE800 really caught my attention.
What struck me at first is their musicality. It's hard to describe but they sounded very natural, far from the over-analytical AK3003. They still managed to remained very detailed, especially in the treble. It's truly a beautiful sound, full of life and dynamism. And incredibly fun.
Now let's be clear: the IE800 are bassy headphones. They may not please the ones here looking for a neutral/reference sound. The bass is strong, powerful, and give a solid body to orchestral music, pop and energetic rock. In terms of quantity, it is more present than on the W4 but obviously less than the monsters FS Atrio M5. This is a strong improvement over the IE80, which I returned because I found the bass awfully muddy and veiling the mids. BUT: the bass still slightly bloaty and somewhat overpowering, esp. on bass-heavy tracks. It lacks the definition and precision of my W4. The AK3003i bass is at the opposite: flat, controlled, very tight with short attack and decay.
I found the treble very forward, and it added excitement to the sound. (That being said I've been raised with Westone which are known for their smooth and discrete highs.) I did not notice any sibilance which is positive since seing the word "sibilance" in a review has always been a deal-breaker for me.
At the end of the day I have to say those are the most fun IEMs I've heard.
I was going to order a UM Merlin but after demoing those I am reconsidering. I'll try them again this week and will try to update this post.
The price was 1,149 SGD.
PS: As you saw this is my first post on HF and English is not my first langage so please be indulgent