It's going to vary depending on your own income outside of investments, your age, your ultimate goals, whether you want/need the income to live off of, and all kinds of other considerations.

This can indeed provide a steady income stream and considerable financial stability over time.

The only draw back I have is that AMEX isn't accepted everywhere but otherwise we like our AMEX Blue Business Card.

This just have to pick a market with a draw and being renovated.  

While they typically have considerable deferred maintenance, we're getting great terms.

The wider local region also seems to have a lot of tourist draw.

Then again, if you’re talking about a mortgage on your personal residence, and you live in a state with an unlimited homestead exemption for creditor attachment like Texas or Florida, there’s an asset protection consideration as well.   

Drawing from your industry expertise, what would you consider the average success rate for Fix-and-Flip investments, and which localities offer the most potential?

I'll definitely take that into consideration when I make my RE move and will look into some meetups.

But for an OOS investor one consideration is access to support, first of all PM & contractors, and you have more choices in the much larger Milwaukee metro area than in a smaller submarket.