The reason why iDevice tend to work flawlessly is because there is this thing called iTune, which either asks you to only buy iDevice compatible music in the first place or forces you to convert your music before loading to the device itself. You get the compatibility not because iDevice is better on the firmware, but because the heavy lifting has been taken care using some clever trick. The problem with FiiO is that they don't have an iTune of their own to optimize the files and check for compatibility before they are loaded onto X3. Therefore X3 itself must be able to read everything and try to play them back. That will require more intensive coding than that on iDevices and ultimately lesser smoothness and more buggy in operation. I think it will be much easier for them just to write a FLAC encoder, then require everyone to convert all their music to a fully functional 24/192 FLAC setting before loading, but then I'll probably hate it as much as I hated iTune. I remember an article from a few years back comparing OSX to Windows - it mentioned that although OSX ran on a much slower hardware back then, people still believe it ran faster. But in actual measurement, OSX did run slower. It is just that Apple had managed to pre-load the interface up so people thought it ran faster. But in reality it still had to wait for the library in the background to load up before it can actually work. Where Windows seemed slower because it didn't pre-load any interface but only came out when everything had been loaded and ready to work.
I have recoded / optimized my whole music collection so 99.95% of the time they will just play on any device I loaded them on. Basically I have done the job of iTune, except that my optimization is toward maximum compatibility to non-iDevice DAP since I do own quite a few of them. The funny part is that I have encountered more problem asking my iPod Nano to playback mp3 file (*when they are encoded via non-common setting) than I have with X3. It is a pain in all honesty to get everything runs right, but in return I have faced much less problem these days with any DAP, regardless it is X3 or an iPod Nano.
Sometime it is just the little thing that gets you. Remind me of
this.