Redfin, realtor, etc all obviously have their data... are there other websites any of you use that might be suitable for more data-savvy people who are interested in e.g. cross-market analysis or getting more refined data for individual markets?

The first question you have to ask when you've found a suitable property:  Is doing an STR legal in the community or HOA? 

To most investors, 1031's aren't suitable since it involves the holding period.  

When a tenant leaves, the configuration they leave it in has the highest chance of being suitable for the next tenant with minimal construction. 

@Michael Smythe pointed this out.But I would say it was also a self-managing landlord-suitability problem. 

Purchase price: $181,000 Cash invested: $40,000 Sale price: $265,000 I assisted a client in finding a property that would be both a suitable primary residence for him, and also a home that he can add value to potentially sell for a profit.

It's a matter of tolerance and being made aware their boisterous manner is not suitable. 

Takagi makes a model that is suitable for minimal usage. 

We are offering NNN leases on properties suitable as vacation rentals purchased in the $600k-$1.5mil or so range, in the greater Palm Springs area. 

Build a Relationship: Building a strong rapport with the real estate agent can increase the chances of them sharing off-market opportunities with you in the future.Remember, working with an experienced agent can significantly enhance your chances of finding suitable off-market multi-family deals.