i've heard the cronus(integrated) a/b'd with some big names and found it to be close. its sweetness reminds me of the classic marantz 8b, which is the biggest compliment i could pay it. there are many expensive tube amps out there that are just a bit better...but in this hobby of diminishing returns for what you get soundwise, i suspect the zeus, like the cronus does comes as close as any giant killer.
