My impressions after a week with not one but two pairs of EL-8 closed...
The EL-8 on certain source material sounds weird in the upper mids lower treble region. Vocals sound unnatural and completely "off". If you have source material that you truly know how its supposed to sound I'd suggest trying all of it on the EL-8's before committing to a purchase. I used almost exclusively FLAC and DSD64 sources that I know fairly well. Oddly after the first two listening sessions I was motivated to write a review singing the praises of Audeze EL-8's and how they're the best value in headphones. This was primarily because the "weirdness" I describe only presents itself on certain tracks. As I have moved through different headphones AKG K550, HD600, HD650, Westone W40s, and now Audeze EL-8C I have found that there are plenty of tracks that sound great on all of them. I call these tracks balanced/easy source material. On this material the EL-8's were wonderful. Refined mids and slightly rolled off highs, and I believe I even got a taste of the sweet sweet Audeze bass. But what I've found is that a negative definition works better as you get to higher end headphones. In other words, "how much of the music I love sounds annoying or horrible on the headphone I'm analyzing". For me the deal breaker that got the EL-8 "voted off the island" was Norah Jones in DSD. The EL-8C makes her sound like she's singing through a horn. Or like the original vocal track was removed, then run through an AM radio, and re-recorded with the rest of the high fidelity instrument tracks. This is where the term "weird vocals" comes from when describing the EL-8's. I listen to classical, rock, alternative, jazz, country you name it. Even trance and dubstep when the mood strikes me (fwiw dubstep/deep bass sounds great on the EL-8). But if I spend the extra money to buy music in DSD and any of it doesn't sound right (or enjoyable) with the gear I'm auditioning then it must go.
My suggestion for EL-8's is to buy from Crutchfield or anyone else that has 60-day refund without a restocking fee and make sure to listen to all the music you really love before deciding these are keepers.
I am half tempted to try the open-back as people say they sound way different. It's just the EL-8C are so far off the mark (for me) that I doubt the open back will cut it. I am oddly drawn to the LCD-2's now that I've had a taste of Audeze bass and will be doing some extended listening at a local dealer next week.
My $.02.