I've tried quite a handful ribbons these last two years. And listened to many, in online reviews.
The X1R surprised me A LOT when I got it. As soon as I held the package in my hands, and opened it, I could feel this was a better mic than anticipated.
Because I liked it so much, I later ordered sE's VR1 Voodoo ribbon mic, sorta like the older, more mature brother (or sister) of the X1R. I was surprised at how close they are, performance-wise. So I returned the VR1, as I feel it didn't add much, for the premium cost.
I've also compared it with NoHype Audio's LRM-2b which I also own. The X1R has the same high-frequency extension as the NoHype mic, but the latter does have louder highs. Around 4 dB louder, on average, between up til 11.5 KHz where their frequency responses meet again.
BUT, I mostly prefer the X1R. It has something going on, that just makes it sound so... Nice. I can't find the word for it. Perhaps it's the transformer, some harmonics, or simply its frequency curve.
Note: get the DM1 Dynamite inline-preamp for it! Read my review of that one, to see why.
Only thing missing: I would LOVE a hipass filter switch (preferably with two options) to tame the proximity effect (which isn't quite as intense as it can be with other ribbons, by the way).