Do you have the knowledge and insight to handle any LT complaints and are you set up properly with your bank and security accounts and can easily collect the rent, etc?

We also chose the wrong property management company who promised they could turn SECT 8 units easily.

If you have plenty of extra income each month (or indeed, if you do have the ability to pay down 80% of your mortgage now) - you can easily make extra principal-only payment/s! 

If possible, I would look at the building to see how easily I could merge 2 spaces together, providing a tenant a 1,400-1,500 sf space complete with a small 150-200 sf office w/bathroom, and the rest shop space.

I had enough to cover it, and the deal ended up being a great win overall. 

If your friend recently made 3x his mortgage, but it was a spring/summer month, he could easily struggle to cover the rent in the fall and winter months. 

Now applying this to Philadelphia, you can easily go into areas of North Philadelphia or areas of SW Philadelphia just as examples and find properties that pencil as BRRRR's as easily as it is to pick produce out at a grocery store.

You can also use FHA with 3.5% down as well although may be harder to win in a more competitive market.

There can be a lot of details to this, and one can easily get lost in the details but pull-back and keep vision of the fundamentals as it really is rather simple. 

That could be found in the title search pretty easily.