No experience with Backert, have heard they are great. I did own the original Zesto Leto and it was an amazing preamp. Easily the best sounding preamp i have ever had first hand experience with. Amazing clarity , really commits no sins. I would urge you to demo one.
George and Carolyn Counnas are some of the nicest people you will ever meet in hifi Service from them is first class. I had some upgrades done and they were awesome to deal with.