I finally, and unexpectedly, got the chance to demo the Z1R at CAF this past weekend. There were two of them at the Kimber Kable booth. They were driven by the Sony DMP-Z1, but I was also able to listen on my ZX707 that I brought with me due to the 4.4mm termination of the cables. This headphone has really nice bass thump! It doesn't have the same clarity, texture, and immediacy in the bass as an Audeze or the SR-X9000, but in terms of heft, it was distinctive. I would pick the Z1R's bass over either of the Meze Empyreans (1 or 2). The soundstage didn't feel closed-in, which is good for a closed-back, and show conditions aren't the best for evaluating soundstage anyways. I don't think it's as wide as the HD820.
I did run into peakiness in the treble. On the song "Titanium" by David Guetta feat. Sia, the hi-hats starting at 1:00 were pretty grating. That song is just very aggressively mastered, so some glare is inevitable, but I had to turn down the volume because it was too much for me. Oddly though, I thought that cable rolling actually helped here. The peakiness was most noticeable on the Kimber silver cables, and the other Z1R had the copper cables. Those hi-hats weren't as grating when I used the Z1R with the copper cables, even when I turned the volume back up. I listened to the two one after the other after about a minute and a half of listening to the silver cable, and I don't think brains acclimate to a sound that quickly. There was no stock cable at the table though, so I don't know how it sounds stock.
Back home, I listened to the same song on my sticker-modded Z7M2, and I kind of missed the Z1R's sound. Bass was not as impactful or physical. The treble peaks on the hi-hats were reduced, but also the sense of clarity that I heard on the Z1R regardless of the cable. The Z7M2 sounded a bit grainy in the treble in comparison. The Z1R is probably the only headphone I heard at CAF where I went home and wanted to upgrade.
Edit to add: Another advantage to the Z1R is its improved comfort over the Z7M2. I need to use a headband cover on my Z7 since the inner sides of the headband will touch my head and be uncomfortable. No such discomfort existed on the Z1R.