I got some more time with the OAE1 today, and while I think the headphone has notable flaws (notably, ergonomics both in terms of comfort/size accommodation and the ability to get the intended sound with the angled/upfront drivers), my feelings have improved.
I can't say, at this point, that the OAE1 sounds like I'm right there with the music (that is, that it transcends the medium of headphones). But it also doesn't sound quite like a traditional headphone.
That's strange, and it's not objectively a positive or negative. It depends on what you're looking for. I've always had more of a connection to the sound of headphones.
The greatest manifestation of the driver orientation of the OAE1's, to me, isn't a huge soundstage, but rather the simple (but strange) sensation that the music isn't coming from the headphones. I know I'm wearing headphones; I can feel them, and while comfort isn't a huge issue on my head, it's also not fantastic. But it doesn't sound like the music is coming from the headphones. It sounds like I'm hearing music played from an external source, and hearing it through the external grilles of the OAE1.
The technical capabilities are all average, in my estimation, which might be what ultimately makes the OAE1's unique qualities not quite worth the tradeoffs. Bass is elevated and present, but lacks definition. The timbre in the midrange can be problematic in some materials. The dips in and unevenness in the treble can have tangible and detrimental effects to the naturalness of sounds in those frequencies.
I'll have to gather my thoughts to say more, but for now I've heard enough. I may not be in love with it, but it's unique enough. And I'm too intrigued by the EQ/modding possibilities to return it. So I'm keeping it.