I replaced a Benchmark LA4 preamp in January. As I was searching for a new preamp I heard the ET6 SE at a dealer, but was not impressed and eliminated it early in my search. I wanted more detail.
The 1.4 Rhumba Extreme was recommended, but I could not get to a location where I could listen to it. It seemed to have the detail I appreciated in the LA4 while providing an improved soundstage. I decided to go with the LTA MicroZOTL Level 2 which compares favorably with the Rhumba but at a much lower price. They just released the Level 3 upgrade at a similar price to the Level 2.
So much depends on the rest of your system. It sounds like you have a great relationship with your local dealer. Perhaps you could bring both home for a test drive in your system and keep the one you prefer?