It would be great to see full reviews on both the Darlington and iFi Zen preamps. Two very different approaches, the iFi Zen being a mass-produced, op-amp based design with surface mount components and the Darlington being a J-FET transistor based design with hand-soldered, through-the-board components.
The iFi has received stellar reviews across the board while the Darlington products are attracting a lot of attention for their classic design and construction approach. It would be interesting to see if the iFi Zen lives up to the hype, how the Darlington MM-5 compares at a similar price point, and whether the Darlington MM-6 is worth twice the price of the iFi Zen.