The short and simple of it is this is the best DAP for the price I have owned. I have used all the main stream players, (IPods, Zune, Creative Zen Player, etc) and I will never go back. Besides the great audio quality, the battery life is unparalleled. I have played with my friends iBasso and Colorfly and although they might be a bit better (maybe) with the full lossless, i still like the full freedom of the Jet Effects. Besides, it was much cheaper than what they paid.
 
If I had to change one thing, it would be the screen, its touch interface works most of the time, but with cold or dry hands sometimes it needs a second tap. Of course the tactile buttons make up for it.
 
For reference, I own the following headphones for comparisons.
 
Bose IE2, Bose QC20, Ultimate Ear UE6000, Sennheiser HD590, Sennheiser OCX 880, Denon C751