I have used Joe's Juice, Vinegar and Kalk. My biggest mistake was waiting too long to tackle it. When I can get a good hit on one (generally, this means in the gullet if large, and a good pasting-over if small), Joes Juice and Kalk work great. Vinegar works if you can inject it. Heating the Kalk or Vinegar in the microwave seems more effective as well. With the amount I had, I would switch between vinegar and kalk just to keep the PH from going to one extreme or the other.
I will say this about Joes Juice: the injector is great, and you can use it with the vinegar or kalk later. The plastic "needle" seems to help a lot. For me, much better than just the syringe. It *can* clog, but just back it off a bit to clear. If it clogs, don't push the plunger too hard or the tip will fall off, forever lost in your live rock.
Another trick if clogging is a problem (when I switched to kalk, this got worse) is to clip off a small amount of the "tip" of the plastic "needle". This widens the hole slightly.
Whatever you do, go after it as soon as possible. An infestation is a real pain... you kill one and 4 more appear out of nowhere!
Good luck!
-Mike