Looking at these specific preamps give me your opinions

@brbrock The 'Revelation Raven tube preamp by Spatial Audio', has a substantial Pedigree, and is also the work of individuals who have taken the Design Intent and selections made for the circuitry that is beyond usually discovered in the main stream manufacture arena.

Valve Circuit Enthusiasts are extremely fortunate to have this model as competitively priced option.

I would love the chance to be seated om front of one.

For the Short List it is well worthwhile to attempt to have a experience of one in use.  

Add Audio Research and Rogue to your list. 
Rogue RP1 is an enormous bargain and a serious competitor. 

also listen to Ayre.

I have, and really enjoy the PS Audio BHK preamp. It has five inputs, and each input has both balanced and RCA connections. You could actually hook up 10 devices at the same time, so long as you only played one (either the balanced or RCA) at a time per input. It also has both balanced and RCA output, and I have them simultaneously attached to a power amp - the balanced to the Zesto, the RCA to the Coincident. Then I can choose which one to use by only moving the speaker cables in the back, which takes mere moments. 

It has a tube input, and mosfet output. When you roll in different 12au7's you can really hear it - I have enjoyed shaping the sound by thoughtful tube rolling. As a bonus, it has a very nice internal headphone amp that powers my Audeze headphones with ease. 

Anyway, that is the one that works for me...