I've not heard any, but a friend whose ears I trust says they're somewhat edgy and not very musical sounding. What he says leads me to believe that they sound about as unattractive as the Sovtek 'N7s--thin and edgy, exactly the opposite of the sound I like.
BTW both of us love the sound, overall, of the Ken-Rad copper-post-hollow-filament-tube blackplates, staggered or not--slightly warmly balanced, NOT edgy in the treble, and very musical and attractive. He LOVES the sound of the similarly warmly balanced (and expensive) Brimars, altho they're a little edgy in the treble for me. I find the black-T-angleplates by Tung-Sol and Sylvania to be slightly thin and edgy. RCA black-ladderplates seem to do nothing right and are just boring.
I stumbled into 1 Raytheon-branded Tung-Sol roundplate but haven't listened carefully to it, as I'm looking for a mate for it. They're VERY expensive (as in over $100 each if they test strong), and I may sell the single.
Have you seen this rather-comprehensive thread on 'N7s? http://www4.head-fi.org/forums/showthread.php?t=119638
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