I'm not an expert, I've only had a Sennheiser CX300, a Philips 9850 and my lovely Hippo VB. Since now, I like the presentation, highs are better than in the Hippo, but I'm not very satisfied about sub-bass and mid-bass region. The first one was better in the Hippo by far: more natural, more deep, I was able to feel the skin of the drum vibrating. In the XP3 the extension is good but they miss a bit of impact. About the mid-bass region, probably I go used to the lack of them in the Hippo: sometimes mid-bass are too much for me and cover singers' voice. I don't know if it's a problem of burn-in, we will see.
So, globally I have to say they're a good pair of IEM. BUT the cable noise is REALLY annoying. If you want to listen to music while walking, you'd better insert the cable in your jacket to keep it firm...or buy another IEM!