Somehow, I had managed to miss out on the arrival of the Rx. Perhaps it was because I finally felt relatively satisfied with my iMod/ALO/RSA Shadow combo feeding my JH-13s. Nevertheless, I am waiting on Justin's Pico Slim, and now I stumble on to the Rx. The power supply is very attractive on the Rx, and certainly Jerry Harvey's recommendation and jp's review are very persuasive. However, I am concerned about: (1) the prospect of hiss; and (2) the size. While the size is designed to match the iPhone form factor--and I especially like having I/O on the same panel--I am also concerned about its size when portability is a key factor [that photo of the Shadow and Rx together is much appreciated]. So, will ponder for a while.