Not so great.
Had them for 3 years and results were not so good. I had some trust issues with them. They blamed so so results on "excessive thatch buildup" and bad soil. Dethatched the lawn and they left me same "excessive thatch buildup" note even afterward. Basically, lawn did get better and I got tired of them blaming bad soil for everything. Tried to cancel and salesman was push and kind or rude. I will spend the same money on top dressing with compost.