I love the Pendant with the VO and VC. (It’s an Amps&Sound / ZMF collaboration, now discontinued but lives on in largely the same form as the Amps&Sound LeeLoo).
I believe you can still find them used on here for around $1800-2000.
It’s a neutral leaning tube amp as I understand it, and in fact it did seem as fast and crisp as my solid state GSX-Mini, but with some added smoothness and ease when compared to the Mini (that’s the best I can describe it).
I echo the recommendations here for Cayin HA-6A (if you like warm sound) and Amp & Sound (more neutral sounding). Quicksilver has some fans here in the community (never heard myself).
There are many options. I recommend checking out “The (Un)Official Amp Thread For ZMF Headphones” where lots of ZMF owner share their tube amp knowledge: