Here is a review (german language).
In a nutshell:
Devialet Reactor 900
/ incredible bass
/ good for Trap / Hip-Hop music
/ not really a HiFi speaker
/ app is not that easy to use (compared to Cabasse app)
Cabasse Pearl Akoya
/ room calibration
/ also good bass, but sound is more HiFi capable
/ app is easier to use
In a nutshell:
Devialet Reactor 900
/ incredible bass
/ good for Trap / Hip-Hop music
/ not really a HiFi speaker
/ app is not that easy to use (compared to Cabasse app)
Cabasse Pearl Akoya
/ room calibration
/ also good bass, but sound is more HiFi capable
/ app is easier to use