Also if you have rental units you want to make sure that you have sufficient reserves should the need arise for a major repair. 

You will eventually have some major repair or replacement needed.  

Are there major employers in the 30-50 miles radius?

Your last inspection should have caught any major issues assuming it was no more than 6 months ago (units should be inspected every quarter).

The one major stumbling block is getting a mortgage for the remaining 80%.

However, the real estate landscape continues to be strong compared to most major cities in the country.”

Lastly, look for access to mass transit, major traffic routes etc.

It seems that a majority have questionable reviews.

A majority of tenants (retail and/or industrial commercial) are so use to NNN that if you mention anything else it is almost a turn off. 

Like you said, it's working for someone so I'll be curious to hear some others input.My thoughts exactly - the $800 / m is not net as you have to figure in the dues - which can be a major hastle .One other factor is if 50% is rented  and / or more than 10% controlled by 1 entity - owner then this project will not qualify for FHA/VA financing which is key in condo market.