Have to say, I still have my UE900 and they are still my best IEM. I tried the M200 recently but as much as I enjoy their signature for it's bass, I still prefer the overall package of above average isolation, comfort, detail, and signature the UE900 offer. It's bass works very well for most of my music while vocals, stringed, wind, and percussion instruments are so clear and vibrant.
after using the M200 for a week it is like a breath of fresh air to switch back to the UE900.
Could you elaborate on why you still preferred UE 900's sound signature over the M200 please?