Is property management a good business?

[Christie Gahan]

Is property management a good business?  It seems like the revenues should be up over a 5 year period because rents are up.  At the same time, costs have not changed must or are lower.  Any thoughts?  At what point, would an investor be wise to own or co-own a prop management company?   How many doors ( B or C) can I person manage?  How many people to run a prop management successfully?