I like this about them too, great for atmospheric rock I think.
I have a modded YH-1 and a K400 so I can attempt to answer your question. The YH-1 sounds almost nothing like the K400 besides a general smoothness. The K400 was a grand soundstage, the YH-1 has barely any. The YH-1 (modded and with EQ) has fast impactful bass and has a largely visceral sound, very lively. The K400, as you described, have a more subdued hypnotic effect.
If you don't like EQ you should hold out for a HP-3 or YH-100, though I take it they would share most of the YH-1's values, but with better bass extention.