I also am worried that REITs NAVs track/follow and are highly correlated to underlying real estate prices [commercial, primarily, although I guess there are some residential REITs as well], making it less of a dividend play [in my eyes] and more of a gamble on real-estate upward price movements. Which tend to blowup, ginormously, especially in the scale of some of the referenced REITs referenced in the links above [quasi-diversified, location/sector specific, EG Healthcare in XYZ state]
Not that landlording isn't highly exposed to underlying property values either: of course they are.
That said, I am totally for the diversification benefits of a [small] allocation to REITs in ones portfolio, such as 5-15%