Property Manager Question...

My question(s) is for those of you out there who own residential real estate (apt buildings, etc.) and use property managers.

What kind of responsiblities do you “typically” give the PM, and which do you hold onto yourself?
How are they typically compensated (% of GOI?)
How do you go about finding good ones?

My partner and I own a 12-unit building and some condo units and do all of the management ourselves (in addition to fairly demanding full time jobs and family responsiblities). We like being hands-on and making sure that things run smoothly, but also realize our time and energy limitations.

Thanks for any thoughts.