My gf owns a clinic that does this (and other cosmetic procedures like Cool Sculpting, botox, etc..)
Yes it works. No it isn't permanent. It will come back to normal (whatever is normal for you that is) in a few years.
It will greatly retard the growth of new hair, but gear is always going to have it return later on.
If you do decide to do this, I suggest you look on Groupon for discounts. Not sure where you are located, but here in S FL it is very competitive. You can get six treatments of a large area for about $299. And you will need six treatments. Or more.