Both are stunning speakers.
Could you tell more about your requirements?
Going only by what you have said:
Punchy bass: neck and neck.
Non-fatiguing treble: hands down ML, thanks to those stunning ribbons.
I audioned both in very different environments, so take it with a pinch of salt.
One additional pro i found in favour of the 60xti is extraordinary imaging and soundstage. In my limited experience, no speaker has come close.
Regards