I have about $15000 AUD to spend and am about to audition both these units as I believe my preamp is the weakest link in my system & they are about the same price.
I have not heard them back-to-back. But I expect the PMG to have greater transparency with the XP-12 to present with more warmth (not that the PMG is cold, rather it is neutral).
Why do you feel your current pre is inadequate? What is it?