Am currently nearing the end of IPL treatment with a reputable dermatologist. Cost of the treatment is $800 per session. The first session resulted in very little, if any change. Perhaps a dozen tiny "coffee grounds" resulted. Dark spots, which were gone over twice each, darkened but never flaked.
The second session was at a higher setting and was somewhat more aggressive (the doctor explained that they start off conservatively to avoid any complications), but the result was the same, namely nothing measurable at all. Perhaps the photos taken before each session will prove otherwise, but what is visible to me is far more important than what the camera might see.
Third treatment was a spot treatment (at my request). The cost was $200. A different hand piece was used, and the settings increased. This time, results were apparent, with crusting over of spots and then pink skin revealed beneath them once they flaked off.
However, one prominent spot (the one that irks me the most) seems to still have some pigment remaining. Perhaps another spot treatment will take care of it. Overall, however, when used as intended (as a full facial treatment), I found it largely ineffective and a complete waste of money.