refinance potential rental to 15 or 30 year mortgage?

[David Cole]

I will most likely move in with my fiance in a year or so & rent my condo out. With mortgage rates very low, I'm thinking of refinancing my condo in anticipation of this move.
Currently my mortgage principal & interest, condo fee, and property taxes are $2,100/month. My current mortgage has 94 months remaining and is 3.25% fixed.
The condo would rent for $1,500/month. So I'd need to contribute $600/month on top of the rent, leaving no cash flow for repairs or whatever.

I could refinance to a low/no cost 3.25% 15 year fixed mortgage & the monthly principal & interest, condo fee, & property taxes would be $1,433/month, leaving $57/month in cash flow.

Or I could refinance to a low/no cost 3.875% 30 year fixed mortgage & the monthly principal & interest, condo fee, & property taxes would be $1,150/month, leaving $350/month in cash flow.

I have no intention of selling the condo, so am leaning towards the 30 year mortgage for the extra income. But I have no experience with this type of decision. Do you have any recommendations or tips?