Help With New Preamp Decision

Like most of us, I am constantly in the process of slowly (as funds allow) upgrading my system to what most would consider "mid fi" or low end "hi fi". I have been reading a lot lately on the subject of SQ upgrades, and what comes up frequently is that the preamplifier might be the foundation of moving to the next level as I upgrade.

True or not, that is the direction I have decided to go....my virtual system is listed. And yes I know I need to upgrade other components as well, so I'd like to keep this on the idea of a preamp.

In doing a LOT of research, I've come across several preamps that I am most interested in and would appreciate some ideas/thoughts/input/recommendations. I want fully balanced XLR with RCA inputs and outputs,  be tube based, and I have no need or desire for a phone input. Max budget is $6,000.....or just a few shekels more.

(1) Aric Audio Motherlode XL $6,125 - Incredible reviews, Aric has a phenomenal reputation, and seems to be an all around great builder in this field - https://aricaudio.com/products.php?product=MLXL

(2) Backert Labs Rhumba 1.4 $5,000 - I have this lower on my wish list, as it is Backert's entry level preamp, what I'd really like is the Rhumba Extreme....but no way I can justify the $8,500 price. And finding a used Rhumba Extreme 1.3 has proved impossible, though I'm not opposed to it. 

(3) Don Sachs and Lynn Olson new Raven (Revolution) preamp $5,000 - His reputation alone makes this preamp important, and he is an all around great and giving guy of his time. I've communicated several times with Don, and he flat out tells me this is the best preamp he has ever designed by far and is a "cost no object" project. I think that production starts Jan/Feb this year (being built by Spatial Audio Labs) 

(4) Atma-Sphere MP3 Mk 3.3 $5,650 - Venerable favorite, it's a well known and well reviewed product http://www.atma-sphere.com/en/mp-3.html

(5) Linear Tube Audio MicorZOTL $5,750 with balanced inputs and Level 2, see this well reviewed and well thought of brand a lot  

Thank you in advance for your input