Here is the only one I have found. It has to be translated via Google Translate.
alpha-audio.nl/2017/07/review-pass-labs-xp-12-voorversterker/
The article is fairly short. They do compare it to an XP-10. For the most part they seem to think the XP-12 is better in most areas. The only thing that is concerning in their review is the last sentence: "Still, someone who prefers punch and attack may find the XP-10 better on that level."
Here are two paragraphs from the article:
"Nothing is more beautiful than real 3D rendering from two speakers. And that is exactly what the Pass Labs XP-12 can do. We hear effects left, right and behind us with the greatest ease. With the right music of course. But to give an example: Opera of the album Metropolitain. We really hear the effects shooting through the listening room. Beautiful.It is also striking that the voice of the XP-12 is higher between the speaker and that it is less 'pressed' than the predecessor. Now that seems to take away some energy at first glance. But longer listening teaches that it brings peace and presents more neutral. And that's nice for longer listening sessions. Still, someone who prefers punch and attack may find the XP-10 better on that level. "
Keep in mind the above is translated, so not sure if the words and context have the same meaning as if a reviewer was writing in English.