Most transactions between friends or loved ones fail.

Quote from @Trent Reeve: i would think they would have more amenities than a non-condo.I think the reference was how do you stand out from one condo to another when they are all identical, vs how do you compete with single family homes.

One thing to think about is when doing heloc on primary if you want to refinance you need to get their signoff as well as your primary loan which could cause complications.  

@Annwar MataniA few comments that I don't think have been mentioned among all of the replies that are worth considering:1.

I really like the multiple income streams from one property.

Airbnb is a company so the only way to buy one would be to own stock in the company. 

Set your investment criteria, systems, and rules—and stick to them.2.Tenant management is all about structure.

Investors should fully understand that Section 8 is not a cure-all for Class C & D tenant challenges, it's just trading one set of problems for another.We see too many investors not doing enough research to fully understand all this and making naïve investing decisions.

Not at all bashing REI Nation as I’m very happy with them.

It's nice to make one trip to see all.