I've been doing a lot of research on these two (and other similar IEMs) recently, and so far what I've found is that the super.fi 3 is generally considered to be better than the E2c. If I were able to get one of those two without having to order from the US, I would definitely get the Ultimate Ears. Sadly, I can't, so I'll probably wind up with the E2c.
Anyways, definitely check out head-fi.org. There's lots of very experienced people there who can help you pick out the right one.