I've been a very happy long time owner of both the iaudio X5l and 7. However, I've found that neither supports gapless and the battery life of the X5L is getting pretty bad (the 7 still runs forever on a charge - amazing). So to obtain gapless support I purchased a J3 mainly based on reviews that I've found here and elsewhere. However, I'm somewhat stunned in the step down in sound quality between the J3 and my other devices. Whereas the X5L and 7 both have a full, clear sound that I've always loved, the J3 strikes me as thin and brittle. It seems that no amount of playing with the equalization or BBE settings makes much of a difference - some settings just sound less worse than others. I'm using an identical set of headphones (Westone 4, Etymotic ER-4P, Sony EX-1000) and source files (all FLAC), so it seems the J3 accounts for the difference. I'm curious to hear other's experience along these lines.