what factors should I be looking at when making this decision.  

I've included an example below to help illustrate this.So different lenders have different rates (which do vary even for DSCR loans) but these are factors they all consider.See example below:DSCR < 1Principal + Interest = $1,700Taxes = $350, Insurance = $100, Association Dues = $50Total PITIA = $2200Rent = $2000DSCR = Rent/PITIA = 2000/2200 = 0.91Since the DSCR is 0.91, we know the expenses are greater than the income of the property.DSCR >1Principal + Interest = $1,500Taxes = $250, Insurance = $100, Association Dues = $25Total PITIA = $1875 Rent = $2300DSCR = Rent/PITIA = 2300/1875 = 1.23If a purchase, you also generally need reserves / savings to show you have 3-6 month payments of PITIA (principal / interest (mortgage payment), property taxes and insurance and HOA (if applicable).

How do you factor that unknown future expense into the ROI?  

Need to be sure you include the "unknown budget" and never take the optimistic approach as it is better to have money left at the end than writing more and more checks that were unplanned for.Again, if you can walk through an actual property and compare notes with someone that does it in your area (key factor), you will be way ahead of what a generic book can give you.

My "day job" is in digital marketing (corporate, not "influencer"), so that tends to be my sandbox ;-) Thanks John!

Yeah, various factors kept adjusting but for majority part it was the same sport. 2020, everything changed.

This will heavily influence the best strategy for you.

I have been playing the multifamily game for almost 10 years now, and the GRM is one of my least favorite methods personally since it ignores so many important factors (steam boiler versus electric baseboard heat as an example). 

In his experience, Memphis’s higher-than-typical rent-to-price ratio sounded great in theory, but property management turned out to be a huge factor-especially if you’re not local.

The fact that you are working with a loan officer who is coaching you on committing fraud, you may want to change your circle of influence.