I've spent some time comparing the KingSounds to a LNS, both driven from a T1S. As the hours passed I definitely preferred the LNS. My biggest complaint with the KS is that they sound super laid back. I noticed this the first time I auditioned them, and ended up having to play them a lot louder than I normally listen. At these higher levels, I noticed quite a bit of compression on loud passages...the drivers didn't seem to like being pushed that much. I actually don't mind laid back phones at all, but these took it a little too far for me. There's also a large difference in soundstaging between the two: the LNS has the typical Lambda soundstage, with decent size and really 'tall' imaging; the KS has a very natural soundstage with smaller but more believable sized instruments/sounds. The KS are quite bass shy, with even less sub bass impact than the Stax which is saying something. The KS also emphasize hissing/pops/ticks on the recording. Comparing the mids of the headphones, the Stax is preferred once again. The KS don't stray too far off neutral, but have a sort of echo'ey sound to the mids if that makes any sense. Strings sound much more right on the LNS especially. The KS are also one of the most veiled sounding electrostats I've heard.
I'm sure most people haven't heard the LNS before (plus it's OOP), so I'll try to compare the KS to my 207's later. Note that the LNS is easily one of my favorite Lambdas. I would say the KS actually sound somewhat like a less neutral ESP950 (more treble, less mids), with a slightly bigger soundstage and a bit less detail.
Also note that I was running the KS from normal bias voltage so there might be a little change in sound once I put the recommended voltage, though going by past experience it won't change much.