Summary: The D1 is a must buy for anyone looking to get more out of their current setup. As others have said, bass is more pronounced and full, the highs are crisp. Awesome product, not to mention they power my (250 ohm) headphones nicely.
Summary: In general Audioengine products seem to be extremely high quality at great prices. The D1 is no difference. I have it connected to a mac mini outputted to emotiva 6s powered speakers. wow, the D1 really makes them come alive.
Summary: I have my computer audioengine A2+ speakers connected through the audioengine D1. The computer is connected to the D1 with a USB cable. I then connected a Sonos into the audioengine D1 with an optical cable.
Summary: So I'm an audiophile who mostly listens to analog but wanted to try PC audio on my system. I've tried a lot of different USB DACs ranging from $30 to $2000 and this one fits perfect in my system.
Pros: It has great energy in all frequencies and is very resolving
Summary: I purchased the DAC because I wasn't getting the quality I expected out of my Audioengine A5+ speakers. After some research, I learned that the problem was likely due to the low quality headphone jack built into my Dell laptop.
Pros: Matches well with Audioengine A5+ speakers. Improves sound quality as intended. Visually attractive. Solid construction.
Cons: Had to make a leap of faith that it was a good purchase. Unsure how it compares with cheaper DAC alternatives.