I am sorry I have to tell you that I don`t own both. I "only" own the Tiger but have extensively compared it to the IE900 (and many other earphones) during regular visits of Japan`s biggest portable audio store, where you can basically listen to any imaginable gear. I honestly would not rate either of these earphones over the other, they are both high quality, but tuned in a different direction. I own the Tiger, because it perfectly complements my current collection (see signature). I have several earphones (mainly DD-Hybrids) that are bass heavier, so instead of getting another one with DD (IE900 for example), the Tiger plays the role in my collection of an BA based earphone with focus on super clean vocals and very detailed sound, perfectly suitable for acoustic music or female voices, for example. So I think you should just ask yourself: What kind of music do you want to listen to mostly and do you already have other earphones in your collection? Do you generally prefer the timbre of dynamic drivers or BA drivers? If you need that extra dynamic driver "Oomph" for electronic music etc, get the IE900, if you listen to a lot of acoustic, classic or vocal based Pop music - get the Tiger! And both of them have a fantastic build and fit, just the IE900 is amazingly small and the Tiger looks more extravagant! I am pretty sure you won`t regret either! Hope that helps, best!