Others have said it, Openness, clarity, transparency, weight. It's very much a cliché here but they open the windows and allow the music in. I throw everything at mine, from simple Jazz, through orchestral, and opera, classic rock to heavy rock. They just vanish into thin air superb.
I'm running with a Phono 1 (MM), P50SA and either S300, or a pair of M600's Into Dali Oberon 5's through LS3 speaker cable
Source Wise Well a Linn LP12 (bought a very long time ago, when Linn owned the HiI-Fi media), with the Karousel, Keel , Akito 3/B, Lingo IV upgrades holding a Nagoka MP500 MM Cartridge. Cambridge audio DAC Magic 200, being fed from Panasonic UPD 1000.
Interconnects are SSC for pretty much everything analogue, and SSP for Digital.
Can I see any changes in the future? Possibly, possibly the Phono 1 being swapped for the Phono 2 still in MM configuration ... but that's it, I may upgrade speaker cables, but I don't know, possibly at retirement.