The simplest answer is that it depends. LOL. What I mean is that there really are alot of factors to consider, and different costs associated with each option.
To answer more specifically, I would need to know what exactly is bogging you down about managing your properties. Is it rent collection every month? Is it turnover? Are the repair requests and oversight time consuming? Or is it a combo of all of that?
Typically, you can estimate that a full service property manager will charge 10% of your rent roll.
A full service property manager will typically handle everything from tenant screening and rent collection to turnover and managing repairs.
The pros of this are obvious. This completely clears your plate of handling the day to day operations of your properties.
Beyond the most obvious con of lowering your cash flow by 10%, it also really depends on how much control you relinquish. Some property managers under price rental rates in favor of getting a quick tenant, leaving money on the table. Others may authorize repairs to more expensive contractors for ease of completion, whereas you may have shopped around for a cheaper rate.
If you are looking for a tool to just help you screen tenants and collect rent payments, you may want to consider any number of online automated systems like Zumper, which also gives you the opportunity to post listings for available properties.
If you are looking for someone to handle the turnover, you can expect to pay an average of 5-7% of the initial annual rental rate. This seems high compared to the 10% full service. However, the turnover expense is paid once. If the tenant renews year after year, you aren't paying that fee over and over.
I hope this helps! Best of Luck to you!