Key traits of a good property management company

[J J Moody]

What are some key traits of a good property management firm? 

I already know I will want to outsource this aspect of my rental property business but haven't started vetting PM companies. For those of you have the experience, what are you looking for in a property manager? What questions are you asking in the interview process? Is there anything about the terms of the agreement that I may need to think through in my analysis (beyond the percentage they require to manage the property)?

In reading reviews for some local companies, most tenants seem to dislike the PM and the owner experience seems to be a mixed bag of good and bad reviews.

[Nathan Gesner]

Quote from @J J Moody:

Everyone has their own list of what's important. I think communication and honesty are key. I respond to my owners within 24 hours, even if it's to let them know that I need more time. When I make a mistake, I admit it and pay for it. I am constantly seeking new ways to improve my service to clients, adding new features, improving communication and documentation, etc. I also improve things for my renters because a happy renter pays on time and stays longer. I'm also very honest with my clients about how their property is performing. If they would be better off selling it and investing in something different, I will show them the numbers and explain my thoughts.