If ones ears are too big for wearing the over-ears over the ear, is there a big difference in feeling and comfort? I'm thinking about getting the over-ears but my ears didn't fit inside the cups when I tried them out.

Maybe, but I'd first make sure you're listening to a proper source like the original CD and/or try the same file in a different player to see if it's your sound card. But it also might very well be what viralcow said.   Btw, the word is sibilant :) I'm really thinking about getting the...

Hmm, well. considering the size of an IEM, it's fascinating to see that Sennheiser takes the looks to seriously. Just hoping the sound quality is worthy of the momentum name.