Suggestions on hiring an in house property manager

[Marco Anemone]

I currently own and self manage 16 single family rentals, and while it hasn't been to difficult or time consuming, I intend to continue to grow my portfolio and can see a need to hand of many of the tasks I currently oversee. I'm considering turning over the portfolio to a property management firm, but when factoring the commonly used 10% of rental rate they charge, I may be better off hiring a property manager (perhaps on a part time basis at first, if not full time). Any advice, thoughts or experiences that you can share would be greatly appreciated.