not yet, but:
1) MMCX cables opens the door for cable switching and endanger connections in the future. If the cable is switchable, then custom made cables and different experiments are required. Had xba-z5 and t8ie mkii and I know pretty well how the cable can drastically change the sound and turn headphones in garbage or complete miracle.
2) There are users\owners of EBX who experience troubles with them. QC is the weak point of buying\owning it. For example, recent purchaser had issue with no bass in right channel.
3) I have heard people complaining about ebx sound and never about bs1 official. Have heard quite calm reaction, but not disappointment, especially for the price.
P.s: I would like to try ebx, but no possibilities of reaching the owners and I'm not going to buy them new without audition.