Pros: Excellent sound, no driver needed, superb build quality.
The DragonFly v1.2 sounds clearly superior to my laptop's built-in Realtek HD chip. There is no driver installation needed and I had no problems to use it on Windows, Linux, and MacOS X. The analog volume control works with the OS' volume control. With Debian Linux I experienced once that changing from the built-in sound to the DragonFly put the later on max. volume, which is ear-damaging loud... so beware.
To my ears, the DragonFly sounds better than the X3 in USB DAC mode and far better than my laptop's built-in sound card. If you're looking for a small USB DAC that can be used with any OS, I heartly recommend you check out the DragonFly v1.2.
PS: The 'Review Details' don't show as expected. I would rate 'Audio Quality' 10/10, 'Quality' 10/10 and 'Value' 9/10.