Unlike a hot tub, I have to invest little upfront but can say my properties have unique amenities. 

Scope of Work: Clearly define the tasks and responsibilities the contractor will undertake.

It is not unique or immune to that in any way.

Perform the same task in each app to ensure a fair comparison.Load a property with pictures and details.Market that property.See what your marketing looks like from the public's perspective.Submit a fake application to see how easy the process is.Run a credit/screening report on yourself.Enter a maintenance request, assign a vendor, and attach a fake invoice.Enter charges to the tenant's ledger.Enter recurring charges and automatic late fees.Sign documents electronically.Run owner reports.After testing a few apps, one should clearly stand out.

But I don't think those things you're talking about like costly turnover and bad renters are unique to this market. 

I have been given the opportunity to start an Investor division at my Brokerage.Our goal is to create a team of highly skilled agents who excel in understanding and meeting the unique needs of investors.

Five Unique Ways I’ve Seen People Make Money In Real Estate1.

As for other issues, I have handymen I call to handle or i can use Task Rabbit/Thumbtack to handle issues that are simple and I don't want to handle.  

You'll need reliable local contacts, such as a cleaning crew and maintenance professionals, who can handle on-the-ground tasks.

Managing contractors is in the top 3 of most difficult tasks when managing RE.5.