So far i've only tested it with the MAM but it makes the Zeus sound way more open. Almost as if a dome was unfolding. Very airy and the occlusion effect is gone. I should be putting the finishing touches on the prototype here shortly so that local Head-Fi members can stop by to audition before RMAF
Personal favorite IEM? That's a tough question as it depends on my mood. My current daily driver is the Spartan IV. It's served me well at several gigs and mixing with it is drama free. If I had to pick one to call my "favorite" it'd be a tossup between the Zeus and Zeus-R.
Zeus is definitely for those that desire the absolute best we have to offer. The ADEL will be making it's way to the rest of the Olympus series so there should be something for everyone. I'm actually super stoked to try out the MAM with the Supra II.