What is the best phono preamp you have heard?

I notice that alot of people speak highly of the Aesthetix products in this thread, i have been looking for a new phono pre, and have found an estate sale that is selling alot of high end stereo equipment, and i can pick up a
Aesthetix Callisto Signature, for not much money, has anyone heard this particular preamp, and would it be worth $900 ??