Pros: Fnatastic isolation, strong mids
Cons: terrible soundstage, notorious Shure cable quality, expensive
E3c were my first serious headphones, and whilst I loved them at the time, I would not recommend them to anyone now.
The best thing about them is the isolation, it's fantastic, and the best I've experienced (not tried ety's). However, the cables crapped out on my after a year of use, and an upgrade illustrated to me how incredibly limited these phones are to mids. It leaves you with a "muffled" feeling.
The e3c has since been eclipsed by a huge variety of single armature driver IEMs at much lower price points like the soundmagic pl50 etc. I would only recommend to someone who is really desperate for good isolation above everything else.