Short sale under contract, flip or hold for rental?

[Tri Phung]

Hey BP family! I have a short sale under contract that I have to close by the end of March. We have the short sale approved for $169,000. It needs about $15,000-$20,000 to get it to marketable condition. ARV will be $250-$260k so there is enough margin here to tempt me to just flip it an take the money and move on to the next deal. However, we are considering keeping it and renting it out to have a long term cash flowing property in our portfolio.

Its a duplex 2/1 600 sq ft each unit that can rent out for $900/month each unit conservatively. 

$1800 gross rents.  Taxes will be $200/month and no Hoa.  Insurance will be $60/month. 

Since I can still qualify for a primary residence FHA loan: take out a $100k loan at 4.25% $500/month debt service.

We are still looking at $900/month cash flow taking a 20% vacancy and repair rate monthly.  That's $10,800 annually or a 12% cash on cash return assuming we put in $90k for down payment and repairs. 

Flip it and profit $50-60K now or

Rent it out and have $900/month cash flow and tenant paying down low interest debt? 

Thoughts and risks feedback appreciated.  This is only my 3rd deal so I appreciate any guidance.  I am 33 and want to make the right decision and plan for the future.