The LTA MZ3 and the CODA 07x are both excellent preamps. I prefer the MZ3 myself, having owned both. It might just be a simple case of the color of tubes over the dryness of a solid state, but they are somewhat alike as both are very transparent.
I have heard the Martin Logan’s at audio shows and a friends home. They sound good but the valentinas have a huge advantage in that the bass integrates with the electrostatic panel seamlessly. I don’t think ive heard any other electrostatic speaker with this kind powerful seamless bass output.
My current speakers are the Martin Logan Ethos but I'm tempted by the Valentinas. Have you heard the Martin Logans? What would you say the differences are?