Pick a saloon the has a good reputation. I work in a saloon, but wouldn't let them touch my eyebrows. I do it myself first.
I get regular facials done at another saloon. The girl who does my facials also does my waxing. Although I've had to stop waxing my underbrow because I'm using glycolic acid on my face. The treatments remove all the old skin layers, so the skin under mybrows is very sensitive to wax.
If they are trained properly they will wax the eyebrows to enhance her face. Yes, the first waxing can be more painful because you are removing all the unwanted hair. The key is to have it done regularly, before it all grows back. Less hair to remove, less pain.