A good property manager is worth gold and save you a lot of legal troubles and money. Just a quick example, my girlfriend is a property manager. Bought a new washer and dryer for a landlord. Within a year a waterleak. The damage was around 7k. Landlord had no insurance, so had to come up with 7k. The property manager contacted the manufacture of the washer and claimed on their advertising that they will cover for water leaks for their equipment. At the end the manufactor had paid 7k to the landlord. I know this does not happen often but a property manager get you usually discounted repairs for your properties, can protect you from legal liabilities which can get expensive, licensed property manager tend to use licensed technician for a discounted rate which helps you not to get liable.
We as landlord might think is a easy thing to manage our own, this is true in the events the property does not need anything, but if something happens I will always prefer a property manager handle it. Is just an extra layer of protection but you have to find a good one than it's worth gold.