Hi Bill,
You have tried quite a few preamps. I think you are right in picking the Dude as the best. Even though I have listened to many gears elsewhere, I only have owned 3 preamps so far; the Dude, BAT VK-3iX, and my DIY SST (simple single triode) preamp. To me, the Dude is the best of the three.
My BAT preamp uses 6922s. Even though I probably have used one of the very best 6922 variants, Telfunken 6DJ8s, but I like the sound of 6SN7s better. However, BAT preamps have balanced outputs and more capacitors in the B+ power supply, and I think they contribute to more powerful bass.
My DIY SST preamp is a reflection of my audio/electronic experience. I use premium parts throughout the SST preamp. It sounds pretty good but not finished yet. However, after listening to the Dude preamp, I am not very motivated to finish it up. LOL...
The Dude preamp is a time proven product after decades of continuous improvement from TRL. I have to say that it is very difficult for other companies to match that. I played violin when I was a kid and later on played trumpet in school band. I was an electronic DIYer/tweaker when I was a teenager and later on received my EE PhD degree from UCLA. I have to say that Paul really knows his stuff well.
IMHO, the Dude does have a couple of operational issues. But I can ignore them because it just sounds too good.