I loved the sound on mine, but the retraction mechanism stuck a couple of times in the first few days. I don't think the red actually lights up like the picture on the box. One of the "features" is that the light is not as annoying as it used to be and it was put on the inside of the headset.
I returned them and picked up the 750's. The sound (bass included) is comparable, but not as clear at higher volumes. Also, the earbuds on the 900's were perfect. They are the same size (IMO) as the 700's and fit perfect in my ear. The 750 earbuds are way too big.
So, now I am debating going back to the 900's because they have the best combination of sound and comfort. I'll just have to get a 3 year, $15 squaretrade warranty to cover the thin wires and mechanism.