Ok been a little while listening to my X3 and I have to say I am still enjoying it very much, I have hardly put it down to be honest.
Compared to the X2 the X3 is a great improvement, I love the size and how easy it feels in the hand but not like it will slip out and pray the headphone lead you have on saves it before it hits the floor.
As Twister mentioned the screen is prone to hairline scratches which in every day use you don't really notice. I have taken a picture to show you what I mean and had to take a fair few in different lights to get this to show up but not totally obvious.

The X3 comes with a screen protector so if this bothers you put it on right out of the box.
One thing I would like to see added is the ability to adjust the volume when device is locked, I am not sure what everyone else thinks of this but I think would make pocket operation better.
As you can see in this light the screen looks clean so don't think its going to ruin the screen, it is very faint.
Overall the sound is very detailed and very enjoyable and if you are using Windows 10 media player is the only thing you need to use the X3 out of the box, especially now Microsoft supports more formats.
The X3 will be a tough one to beat at this price range although I do want to try it with an amp and maybe with a pair of Audio Technica MX50x headphones....it is near Christmas after all

*writes wish list to give to wife*
Also I have tested the pause issue when you remove the headphones but I have not had this issue at all so far.