The K414 are closed. I have owned both them and the iGrados, and both headphones have a dark sound signature. But while the K414 have boomy bass and require some modding to balance out the sound, the iGrados soudn pretty good even stock (provided you have the new model without the inner foam), and have a good low end extension (translated: they are able to reproduce deep bass pretty well).
If you need isolation though the iGrados are not what you want, as they don't block any external noise. The K414 are not very comfortable, but not uncomfortable either and they have decent isolation.
Here is my K414 mod, and
here my iGrado mod. I gave the K414 to a non-hf friend who travels a lot and she is pretty happy with them, while I still have the iGrados and use them around the house when I have chores to do.
