Appreciation is never a guarantee so you follow migration and development trends to hedge your bets.

The rise of DSCR only brokers has certainly exaggerated this trend.  

It's clear you're on top of industry trends!

Strong Long Term Trends: The shift to the experience economy continues.  

There is 2 VERY different ways people are going about these sub2's today that make it impossible to say anything on sub2 without defining which one is doing; the "shady-as-hell" popularized trending way, or the well capitalized, professional, trying not to do things shady AND ready to make things right if anything blows back way, which let's be honest maybe 5% of those in the space practice today. 

Identify markets with expanding industries, positive growth trends, and bright economic forecasts.Columbus, Ohio is a great market to consider if you're leaning towards appreciation.

Personally, I stay away from the mainstream trends where everyone who is priced out of traditional long term rentals are now trying to rent out a room or a whole house on the daily. 

For Zillow and Redfin what really matter is the price chart trend of the neighbourhood and not the price itself.

That trend has continued unabated.Now I see people commuting to Boston from Portland, Maine (!!!)

I'm talking about a thorough analysis to include economic trends, population trends, crime, rents -- the whole gamut of relevant data for a particular market.