Disclaimer: This IEM, which is not released in the US yet, is owned by a mutual friend of mine. Measurement has been carried out approximately 3 mm away from the reference plane with a pair of reference filter attached.
According to the manufacturer's calibration data, AX60 is precisely tuned to match the sound signature of AKG K3003, of which I consider as one of the best IEMs ever made. (but not my favorite)
the mainland China. If Astrotec have successfully reverse-engineered the sound quality of K3003 without infringing the patent, AX60 will certainly become one of the top contenders.
CON: There are quite a few: A time-coherence issue (phase-related) between drivers just like Westone UM3X(not as bad as this one), high distortion, bloated bass, and finally, a clearly subjectable peak, which coincides with a half-wavelength resonance of a closed ear canal, in the treble.
Of course, these two IEMs exhibit completely different time-domain & electrical characteristics. Moreover, this match will be completely broken even with a slight displacement of 1 mm.