@Thujone, how the Project Ember sounds compared to Vali?
Ember is quite a bit more spacious and a bit more textured. The low end is not as smooth and warm as the Vali.
Project Ember (6N1P tube): spacious, slightly warm, very textured, more punchy low end.
Vali: intimate, even warmer, more musical. Possibly a slight sub bass roll off as @Soundsgoodtome pointed out.
When I did my comparisons, it was only a 30 minute ordeal. My buddy brought the Vali over on his way to a different event. I need to listen to more sub bass tracks to confirm the roll off but it did very well with mid bass (I trance quite a lot with the Vali).
Overall, the Vali is not far behind by any means. I still prefer the sound of the Ember but that's because I prefer the instrument separation and space more than the musicality and intimacy of the Vali. Plus, don't forget all the options you have with Ember that you don't have with the Vali.