We did for several years and had good results but they have changed their practices and upped the cost so we backed out.
We also had a couple of bad experiences where they placed tricks on us, turning on campaigns that we had turned off and changing the demographics of the campaign as well costing us far more than our original budget.
Would say the last time we used it was 5-7 yrs ago so they may have straightened up their act.
But we do use the info to help us select good keywords for our site and other marketing efforts.
If you use them keep a very close eye.