The economic value of each is drastically different.

Modify analysis to include the following issues with low income, slumlord properties;Budget for building compliance, building and fire codes;Increase vacancy rates, tenants walk off.Legal fees, not just for evictions and collections, but for government matters with violations.You're more likely to have law suits as well, legal aid is free for low income folks, and generally if they bring suit you'll lose, even if you win, you don't really win.Factor in the economic aspect of your ROI, the additional time, effort, hand holding and counselling required with low income tenants, don't forget police calls. 

Economically, it is right up there with the most powerful countries in the world right?

It's extremely competitive to find flips and there are only a few small pockets where rentals make any economic sense.  

A mixed economic neighborhood may or may not be such a bad thing.

Offer and Demand.. basic economics principles...

Here's my assessment on the market in Minneapolis, please let me know your thoughts on my thoughts: ( this would only apply to MN and I do track economical data at my day job)1.

That's assuming you have a solid economy, if you have an economic downtown it's hard for that demand to keep pushing appreciation.

I would not know when the recession will kick in, but I do know that there are key leading indicators to show that we are headed into an economic slowdown.

If you are, there economic value there, that value comes with leverage and (accordingly) a discount relative to "conventional" buyers.