Replacing a Property Manager - HELP!

[Skyler Holloway]

My partners and I have owned a 20-unit apartment complex for 8 months now and the property manager has consistently underperformed; monthly reports are rarely complete/accurate, vacant units take weeks to be listed for rent after constant nagging, communication is non-existent, random fees pop up on statements (NOT agreed to in contract), etc. We've decided to move-on from this property manager and have 3 upcoming interviews for prospective replacements. 

What advice do you have for making the transition as smooth as possible? Based on my experience thus far I don't foresee the incumbent being helpful at all. I fear them withholding random fees mentioned above and in general failing to hand-off any leases/notices/payments to the incoming property manager. 

What are the key considerations I should be looking at? Do you have any disaster stories to share?