I own Amati. I have not heard the X3… but read over a couple reviews. I have also owned speakers with air motion transducers and of different classes of speakers.
These are two completely different speakers in most every way. The Amati is an extremely natural and musical speaker with outstanding coherence across the audio spectrum. While the X3 will have a magical midrange and transparency they will not be nearly as coherent and natural… but more ethereal.
The Amati is the result of decades of refinement in both the sonic characteristics and esthetics. It is in a different class.