Cash then refiance or just take out a mortgage?

[Josh Michel]

I've found a duplex I'm interested in buying in NJ.  I have the ability to purchase it cash and then later refinance, or I can just take out a mortgage for the property.  I would live in neither unit and rent out both.

Which is the better move? Are there any limitations to purchasing cash and then refinancing? Any timing issues I may be unaware of? Do I have to wait to pull my cash back out for a period of time? I can get a 80% LTV mortgage fairly easily, would refinancing a cash purchase be able to get me back to an 80% LTV?

What are the advantages and disadvantages to each?