So far (according to the Zillows and other products like it) my property has appreciated by 1% about 20-40k depending on the site you use - and seconded by my real estate agent. 

Maybe turn it around and say, "At what return would the market risk be validated?"

@Chloe Dawn Murphy if you are ok with putting your fixed rate, tax deductible interest mortgage into a variable rate, non-deductible product then go ahead. 

@Jonathan Wildy if you go this route please make sure that you have a plan to refinance out of these types of loan products eventually.  

Stop seeking approval or validation from others, especially your tenant.

This wasn't a home run for us, but a solid base hit with a product we were very proud of at the end of the day.

When you're looking at a non-QM loan/lender, they tend to have a bit more flexibility in underwriting guidelines compared to the QM product (but that doesn't mean it's a lesser/riskier loan, just that they have different ways to satisfy certain requirements). 

A duplex investment property you are going to be limited to 70% on just about every loan product. 

@Dean Klein The product I am thinking of is a conventional loan with 5% down.

It is also important to know that there are no shortcuts to being successful in real estate—there are no products or tools that will do the work for you, either.