With so many options to choose from, it is difficult to find the best person for the job. In my personal experience property management companies (non sales oriented) are the best for renting. To find the best property manager for you, you will want to do some initial phone calls with a list of questions/concerns and needs that you have, then meet your top choices in person. At the end of the day, its all about who you feel most comfortable with. Most managers will all offer the same services and similar prices - so don't be afraid to dig deeper by chatting with some of their current clients.
Hope that helps.