15 or 30 year mortgage?

[Douglas Goldstein]

So I'm looking to buy an sfr in Fresno as a rental investment.  I would enjoy the cash flow until I retire in 20 years and then most likely sell it to help fund my retirement years.  I have two options for the mortgage and wonder what conventional wisdom says is the best route to take.

Option 1: 15 yr fixed rate mortgage.  Cash flow $50/month not including property management.  When it's paid off in 15 years the cash flow is $1,200/month (if today's numbers never change, for the sake of argument).  Then sell it 5 years later.

Option 2: 30 yr fixed rate mortgage.  Cash flow $270/month not including property management.  Sell in 20 years - before it's paid off.

It seems like option 1 gives me more cash at the 20-year mark, but then I miss out on 15 years of cash flow.  Thoughts?