Backert Rhumba 1.3 vs Herron Reference?

I've not, but can certainly attest to the quality of the Herron 360 preamp; I bought both this line stage preamp and a phono preamp from Keith about 4 years ago, and have had no desire to upgrade from them. I hope you find somebody who has heard both of them you're asking about... 

Thanks @larsman 

I recently bought the Herron, as my first entry into a higher level preamp. I like it but have nothing to compare it to, so was thinking of the Rhumba to compare and get a baseline for my liking. 

Never had the opportunity to audition a Herron preamp but I do own a Backert Labs Rhythm 1.3 . Please contact them for a loaner before you make a decision. Andy is a great guy. I find that my Backert has a control over bass notes that makes a sonic difference in my system. Please check my avatar.

Something else to keep in mind is that Backert Labs would still seem to be going, whereas Keith Herron has retired.... 

I have had Heron and CJ preamps for many, many years. The Heron is one of the best. It would cost more to get a better sounding preamp. Larsman is right. Keith has retired. But my Heron amp and preamp are close to 15 years old and just fine. A CJ ET7S2 would be a close replacement. You may want to simply keep it and consider a different upgrade path.