What are the best home care agencies here in Chicago, Illinois?

The past few years my grandfather and I have been taking care of his wife (my grandma), who was diagnosed with Dementia in 2005. As his support, I come by almost every week to assist my grandfather with her meals, meds, clothing and clean-up. My grandfather was discussing with me to research a home care agency here in Chicago. There are some many agencies out there and I do not know which one that could be creditable 0_0. I am in need of support...

I just do not want to choose a agency that has a bad track record of their home aides mistreating their elderly clients..

Thank You..