Callisto Sig with 1 PS vs MP1 Atma-Sphere

Any thoughts on these pre-amps (only these two)

Aesthetix Callisto Sig with 1 Power Sup VS Atma-Sphere MP1

I'm wondering if anyone has had the experience in trying both of these Pre-Amps.
If so how would you compare them.

Any comments welcome, including dealers.

Thanks