Just updating the thread now that I've lived with the i20 a bit. I'm absolutely loving it still. I have an HD800 now and they still both get about equal head time at my desk. The i20 is nearly as detailed as the HD800, it's just a bit less in your face about it with more lush mids and bass. Soundstage is of course smaller on the i20 but not as small as you'd think. They're only a hair under the HD700 which is only a hair under the HD800. That's only like two hairs of separation. That soundstage ported directly to your ear canal is a really unique presentation too, so I'd say I'm just as "impressed" with the i20 soundstage as I am the HD800 regardless of size. The main negative difference is the i20 just not matching the snappiness of the HD800 and the HD800 feeling just more "effortless" like music is being beamed into your brain. The i20 has more perceivable color to it, but that's not not a negative thing.
Overall, I'm over the moon with my i20. I like to look at both the analog and cipher cables as different listening experiences. The analog being laid back, sweet, with big full mids and a warm but tight bass with non fatiguing highs. With the cipher, the i20 becomes a portable detail monster while having a very energetic and fun sound signature with a gobs of air and bass control.
This is a killer product from Audeze.