First off, I neglected to mention that Zach at ZMF uses the SparkoS Aries as his solid-state reference when tuning his headphone designs. He also owns a HeadAmp GSX mk2, but tells me he uses the Aries over it "9 times out of 10". That's certainly high praise from a respected 3rd party who has no skin in the game (if anything, it's a competitor for his Pendant amp).
I add that just to give you an idea that your Verite probably makes a superb match with the Aries. I have not checked out those latest AT woodies but your mention of "highly resolving, neutral, and transparent" is pretty much the exact description of this amp.
I've heard the Phonitor X somewhat briefly, but not the XE. Honestly I don't even know what the differences are. As has pretty much always been my experience with SPL products, I liked but didn't love the Phonitor X. My quick impression is that it's just a good general performer with a slightly warm, vague presentation, good for most headphones and genres without any particular standout trait. Not a bad choice by any means but also not as compelling as some others in that price range. You;ll note I did not include it in my recent Darko roundup of 4 higher-end headphone amps, despite it fitting perfectly in terms of price. That should tell you something.