I'm also a big fan of the Morrow MA3 interconnects. I use MA3's with the optional Eichman terminations between my Chord Hugo and VAC preamp. I have found nothing better in that application.
I am also trying a pair of XLR MA3 between pre and power amps. In this application the MA3 is less spectacular sonically than my more expensive cables but somehow makes the music more engaging. They are a 1 meter pair and barely reach so today I ordered some MA4 in 1.5 meter XLR configured.
The Morrow cables give me the perception of excellent phase relationships and timing whereby different parts of a musical selection are cohesive as a whole. They are more 3D in presentation than any of my other cables.
Morrow cables are a bargain.
BTW I agree with the long burn in time. I ordered the MA4 with burn in but that is just a start in the process.