Vacant or Rented Unit for Lincoln Park 3-flat Sale?

[Matt OToole]

I have a 3 flat in Lincoln Park, Chicago, IL that I am planning to list for sale in the next 3-6 months.

Currently owner occupied in 1 unit (Duplex up, 3 bed 3 bath).
The other 2 units (2 bed 1 bath each) are rented.

I am wondering if it is more attractive to buyers to leave the 3 bed 3 bath unit vacant when I move out, or should I place a tenant in there and then list for sale?