15 year vs 30 year fix loan for investment property

[Vannak Kann]

Hi All,

I'm in a bit of dilemma, currently i have two property which is 30 years fix loan. first property is 4.75% and second is 4.50. Now if both are rental property, does it make sense to refinance it to 15 fix loan. I have excellence credit, i probably get in the low 3 percent rate. 

In general, what would be the approach to rental property, 15 or 30 years? I'm looking to purchase another property within a month or so. thanks