An interesting comparison, as the X10 and EPH100 actually each possess a lot of characteristics that are more typical of the other's driver type. The X10 is the warmer earphone, also more lush sounding, despite being a BA. Which is more detailed would be a hard call as I don't have the X10s any more but I would say they are probably close; I would say the X10 was more revealing of bad source material and more defined at the most minute edges of sound due to driver speed, but the Yamahas are more extended at both ends, particularly the upper range, and are more tonally accurate. As I said, the midrange on the x10 is more lush, and the bass is softer, without as much punch or quantity, but the notes are thicker in a way, surprisingly so for a BA. The bass is flatter on the X10s, all parts of the bass are presented with equal emphasis, whereas the Yamahas seem to have different peaks in different areas of the bass spectrum; I found the bass of the X10 really enjoyable with music like Shpongle or Infected Mushroom's album Converting vegetarians when tonal detail and texture were required, whereas the Yamahas sound better with music that requires punch and presence like Juno Reactor, Deadmau5 or any hip-hop. Soundstage is wider on the X10s, more immediately impressive, but dynamics are better on the Yamahas as is depth, aided by its distinctive separation; the X10 separates very well, as it is a BA, but they are very smooth and musical despite this. Even though note decay is longer on the Yams, they still sound more analytical in their signature because they are not as warm or colored as the X10 and don't blend the sound. I found the X10s to be very smooth despite having the characteristic precision and speed of BAs, whereas the very distinct sound separation, sometimes metallic treble, and neutral signature of the Yamahas gives them a more analytical feel than most dynamics I have heard.
You won't regret it, the EPH-100 are MADE for more chill house, ambient, etc: music that benefits from good bass and a mid-forward but not overly in-your-face sound.
