Thanks to all who posted on this thread so far. In the end, you decided that with your Audio Research Pre-amp, the PH7 clearly beat the XP-15.
With my Pass Labs XA30.5 amp and Acoustic Zen Adagio speakers, the XP-15/XP-10 combo definitely beat and Audio Research LS-17 SE/PH7 combo.
The LS17 SE has a lot I like about it, but ultimately seems like a poor match with my amp - the highs can be fatiguing and the bass response doesn't seem flat or coherent. I've read about a possible impedance mismatch between the two, Regardless, I like the LS17SE.
The PH7 is a clearly an amazing phono stage. Wonderful sounding and dead quiet. However, in my system, with the right cartridge loading, the XP-15 is every bit its match, and indeed sounds in some ways like it has as much or more tube magic as the PH7. Regardless, I could live with either for the forseeable future, and indeed give a slight nod to the XP-15 for sound quality with brownie points for not needing to be retubed ever, having more gain (and of course also being dead quiet.) On the PH7's side, the remote with loading and the mono function are really fantastic.
We all read so much into these forum comments that I thought I should share my experience and encourage folks to try both of these amazing units as I think it will come down to system matching and taste more than individual quality.