I finally got tired of traveling back and forth on an airplane to get to and from the North Slope because I always had to get my seat reserved late which meant I'd often get the window seat right next to the outlet on the jet engines. I tried to meet this problem with Noise-Canceling headphones but got tired of it quickly because the pair I have (the Panasonics in my sig.) have a slightly muffled sound and are fairly bulky. I had snagged a pair of Marshmallow (FX-33) for my sister to use as ear plugs during the night. I was fairly happy with their sound signature, but wanted a bit better and my sister wouldn't let me try the Kramer Mod on them, so I figured I'd drop the extra $5 to get these. I couldn't be happier. The highs are much more present on these than the unmodded FX-33 and the bass is just right for me, although, this being my first pair of IEM's I had to get used to the idea of the bass being channeled into my ear as opposed to being present around my ear. Comfort wise, I still haven't tried them with the foamies-I'm rather happy with the silicone ear bits, particularly the smallest size ones which fit into my ears much more easily than the default mediums. I also like the cable, which doesn't feel too stiff and coils/uncoils rather easily for me. My only real gripe with the cables is the actual point at which they connect to the drivers-I always feel I'm going to place too much stress at these points and shear the cable through, but so far, they have worked very well. Overall, as a first IEM, I'm glad I snagged these FX-66. Unfortunately, they are sensitive enough to demonstrate the hiss on my Archos AV604 and Sony E507 very prominently, which means I've switched back to my cleaner MD-N707 MiniDisc player until I can....gulp....upgrade my DAP.