Got the Fire Phoenix in today. It shipped on 10/19, so that was pretty fast. The ebay seller was really good about communication. I hope that the quality control issue LaRzZa had was a fluke cause this is a good seller with a good product.
Initial impressions: I plugged into a PC via USB (used an Amazon Basics USB cable I already had and didn't test the included USB). I did a quick 15 minute comparison with my Sansa Clip+ using Ultrasone HFI-780s and various flacs. The bass in the 780s benefit from amping beyond what the Clip can do. Definitely helped in that regard, and had a least as much clarity as the Clip (if not better--but don't want to say more without more critical listening). The reason I tested this first was that it's going to be a gift for my son who has a Clip+, a PC with crappy onboard audio, and an HFI-580. Now that I heard it, I know he'll love having the Fire Phoenix hooked up to his computer. I have no doubt it will make the bass on the 580s sound great.
Next, I plan to spend a little time with it and the Xonar STX and FiiO E17 and other phones. My "guess" (based off audio memory) is that it will at least be comparable to the E17, if not better. For a desktop DAC/amp definitely seems worth the $105.