The aesthetics of the Callistos aren't as striking in person. And since you are seeking "immediacy, imaging, tonal accuracy, details w/o being harsh, and decent bass" you owe it to yourself to check these out.
If I was thinking of buying a used set for $1500, I'd pony up a few more bucks and order a factory-fresh set of Eos I's.
If I was thinking of buying a used set for $1500, I'd pony up a few more bucks and order a factory-fresh set of Eos I's.