REI approach is easily scalable.    

Because later, you can easily use it as your mailing list!

Google and Facebook can easily be swindled and abused.

By keeping your investments local you may be able to self-manage your properties more easily because you're close-by and already knowledgeable about what's required of you as a landlord. 

Quote from @Jon LaBorde: @Jerryll Noorden the way you explained it was easily the best way I’ve heard it explained but the best way I can describe what I was told was “if you get a list of 1000-2000 there’s a 99% chance that you’ll get a deal, I’m not looking for a guarantee because I know it doesn’t work like that but I’m new at this and I’d like to get a running start so that being said I said I’d reach out to 10,000 people just to make my chances 99.99 if you know what I mean.

If they are professional, they can explain this quickly and easily.

It could easily go sideways and ruin your relationship with your relative or get you in legal trouble. 

I find the interface easier to manually update rates across my portfolio, OwnerRez doesn't easily let me match rates across my properties on a spot basis (unless anyone here has other recommendations that uses OR).  

We work with a lot of OOS investors and showings, inspections, and lending can all be done remote very easily. 

There is no single website to easily find them (that I'm aware of) and if there was, I'd imagine you'd be competing with 1000s of other investors.