In my opinion, weigh the following. If your condition is pretty good, wait a few months. Then you'll have more locations that have been doing the scans and procedure. Experience counts!
If you feel you can't afford to wait, choose a site as close to home as possible. Follow up matters -- a lot! You need to be close enough in case additional services are required. What if a clot or restenosis occurs? Who will treat you if you need a change of meds? What about rehab?
In a few months, there will be more of a standard "recipe" to guide any good IR, but even then, I'd try to stick with someone who has had experience with CCSVI specifically.