I know this is a really old post, but I figured that I'd add my 2 cents in the event that there's anyone else out there who may be able to benefit when considering a future purchase.
It seems as though I'm the only one responding here who actually has listened to (read: owns) both pairs of IEM's.
Originally, I picked up a pair of the SE530's, which I found to have amazing sound. After some serious struggle to get them under my motorcycle helmet, I decided I'd branch out and look for something that wouldn't protrude out from my ear as much. I was already familiar with the x10's having worked in an electronics store that sold them, so they were my first choice.
So here's my feedback on the x10's vs the SE530's. Starting with the x10's. They look very badass, let's just get that out on the table right off the bat. They have a great fit and a substantial, and surprising, capacity for sound isolation. They are remarkable ergonomical in how they rest in the ear, and I can confidently say that the x10's are much more comfortable and will stay more stably in my ears for longer periods of time. The SE530's have a tendency to very slowly come out of my ear canal over the period of about a half hour to 45 minutes. I have not had this problem yet with the x10's.
Now, on the other hand, the sound quality between the x10's and the SE530's IS pretty staggering. As previously noted, the SE530's do have much tighter highs and mids, which is not surprising considering that the x10's are made with a single armiture whereas the SE530's breakdown the sound signal into 3 different armitures (1 tweeter and 2 woofers).
The SE530's also do a MUCH better job as far as imaging goes. The x10's are ok... sound is nice, but imaging is pretty shotty.
Overall, I'd say that it really depends on what your application is going to be for the headphones. If you need something that's going to be slim and unobtrusive, the x10's are the way to go. If you're going to be listening to hi quality mp3's and cd's all day long, and frequency response is super important to you, the SE530's are going to be a much more pleasing headphone.
Hope that helps.
And as a final parting thought, for whatever reason, I'm a lot more excited to listen to and show off my x10's than my SE530's.