Approach to managing a 5-20 units multi family vs 30+ units multi family

[Henri Meli]

I'm looking at two interesting deals right now. One involves a multi family of around 20 units. The second involves a 32 units apartment complex. 

On the first one, the current owner has been self managing the units and had a reasonable NOI. On the second one, the property was managed by a professional property management company.

My question to the more experienced multi family owners. Do you take a different approach when letting your property being managed, when you have 20 or less units or 30+ units? Does the approach change, if you live near the property or if the property is further away (in state of out of state)