@Brady Boyer in my opinion (which you asked for) you should not invest in real estate until every penny of your student debt is paid off.

If you leverage every last penny with no reserves a bad cycle will bankrupt you.

My opinion, they don't deserve a penny back. 

Sounds much more fun than staying home and fretting about my pennies.

Don’t sugar coat it or use vague terms.

@Bob Bowling  got to stop and smell the roses.. but its a little silly to get all wrapped up and try to get down to the penny on low end rental stock.. there is either some money left over or there is not .. and what determines that is if your tenant has been kind to you... end of story on that one.

(I'm also assuming that, in either case, you're not deploying your last penny - always keep a cash reserve.)If you can get a prop that produces more than $12k per year in gross rent (the diff between $78k and 90k on these two props) in your chosen market, then that might be the way to go for you if your primary goal is more doors. 

Fund the 401K to the point where your employer matches, not a penny more.

But we are taking about copper wiring, and no breaks in wires in the walls (because hoses burned) and 2 exits in every bedroom (because people die trapped in houses) and non lead paint and no asbestos etc.This is not new, there have been building codes since well before Christ was born.  

. - longer mortgage and more cash flow - especially early in your investing where you need to keep every penny of cash you can get your hands on.If you were sitting on a big mound of cash (100k) then I could maybe see going with a 15 yr mortgage if your goal was to pay it off quick and if the thing was cash flowing anyway.