I haven't personally had them but since no one has replied I figured I'd tell you what I know!
People have variable results like they do with other meds/treatments. I have seen patients have amazing results!! *Some* insurance companies do cover it. What you need to do is find a pain clinic near you that offers them and schedule a consultation and they can submit a request to your insurance. If it is approved great if not you will have to pay out of pocket if you choose to go through with it.
My insurance is BC and might cover it but because I have a high deductible I'd be held responsible either way so I'm waiting until I have the money and then I'm definitely going to give it a shot (not pun intended LOL)
Hope that helped :)