Just for clarification, the J3 doesn't have a line-out which is my biggest problem with it - only has line-in. I have a feeling that I would prefer my FiiO E17 to do all the work. With anything but my Brainwavz M2 IEMs, the sound is rather thin and with good monitor headphones, it's very obvious that the EQ is compensation - not the same as good proper amplification. Granted, the EQ does in fact work better than anything I've tested before and/or know exists and it does have decent amplification. The problem is, for whatever reason, its sound in general is rather cold and probably what makes it not sound as full as even say an iPhone 4 with a FiiO amp.
The even bigger problem with it is that it doesn't have the best DAC. It smushes the soundstage and the stereo enhancement just displaces it within that same amount of area.
The J3 has decent things about it and things which are different and unique to it in good ways, but overall it's disappointing. I didn't even take the basic things into consideration because I expected them to be flawless. That ended up being where all its biggest faults are. That being said, in combination with my M2's, there's nothing I would prefer listening to them more with.