I've been using passive preamps for about 10 years now. I've probably owned most of the passives out there including the McCormack, First Sound, Reference Line, Luminious, Placette, etc. and the Bent is by far the best I have heard. I think I heard something on AA a couple of years ago about these crazy guys using transformers instead of stepped attenuators or pots to control the volume. From there I discovered the Stevens & Billington site and then I heard about Bent. Isn't the web great? Based on what I heard about the S&B transformers, I knew the Bent had to be good especially when I saw the other components that were being used in the design.
AA has had a lot of discussion about the Bent lately and most people who have heard it agree that, in the right system, it is hard to beat in terms of transparency. And it has dynamics and bass that other passives just can't touch.