The main problem with a small-cap REIT fund is if there is another financial crisis will the small capital firms survive? Some of the largest mREITs (Fremont General, Novastar, etc.) crashed and burned during the last crisis so that is a gamble in my opinion. I think it may get you more returns than the large REIT funds/ETFs but there is a higher chance of default as well. I still think you are better off buying VNQ and if you want more yield buy some NLY which did survive the crisis.