I too started with the IPL system.
I didn't have that much facial hair to begin with but I wanted to kick-start my hair reduction and feminization. It seemed like a quick way to get rid of the hair.
I did research quite a bit and while it is effective, by FDA rules, they cannot claim permanent hair removal. They can claim permanent hair *reduction*.
As Rava said, it does very little for light/grey hairs. Whoever you go to should probably make that very clear to you. Recently there has been a development of a new drug that can be used in conjuction with IPL and causes the roots of the hair to get darker and allow more energy to be absorbed from the flash. I don't know what the status is of this additive.
It did remove virtually all the dark hairs on my face, but I had quite bit of grey hairs. Now I'm in doing electrolysis to remove the rest. Because of my facial hair in the first place and the IPL, I'll only have to spend about 10-20 hours under the needle.
For me it was a good compromise.
-Sandy