Theta Casa Nova vs Audio Prism Mantissa

Currently demoing these two preamps and having a very hard time on which one is better overall.  My set up is strictly 2 channel They both perform very well in my system with the following observations:

Casa Nova seems to squeeze every bit of detail out the recordings and then sum. Very good sound in two channel stereo mode. Voices and midrange is exceptionally good for a pre pro

Mantissa is like wise very detailed maybe one or two very small steps behind the Casa Nova. The Mantissa seems to be just slightly better than the Casa Nova in overall musical presentation maybe due to what I precive to be a wider soundstage or blacker background(if there is such a thing) the Mantissa is all factory original 

does anyone have experience with both or either of these units? Looking to get some opinions and thoughts from the community.