Mystery solved. The demo pair I heard and really liked was a 3c whereas the new set I bought was a 3f. That explains the difference in sound. So at least for me and the type of music I mainly listen to (classical solo piano) the 3c is more to my taste. The bigger sound stage of the 3f gave the piano a darker, muddier sound that made it less desirable for me. I suspect for most types of music the 3f is preferable, but for my particular needs the 3c works best. At least I know that I wasn't crazy when I thought the headphones I bought sounded different than what I heard in the store. I've returned the 3f and will be getting the 3c. Thanks to all for their replies.
Well, don't I feel silly.
Only a couple of days ago I was talking to a user saying how I've never heard anybody saying they prefer the 3c's to the 3f's.
Anyway- glad you are getting the one's you preferred - enjoy brother