Yes, Roofstock is a legitimate company. Investors have used it successfully to both buy and sell rental properties. In 2019, they surpassed 2 Billion Dollars worth of transactions on their platform.
Using Roofstock, you can filter investment opportunities by cap rate, return, and their metric for neighborhood quality. Another benefit of Roofstock is that they sell homes stabilized with tenants in place.
Investing in single-family homes remotely is inherently risky. There are so many moving parts. A single-family rental home is a complete business with vendors, customers, and lots of capital requirements.
Roofstock has built up massive amounts of experience through the sheer quantity of transactions handled on their platform. With over 2 billion dollars of transactions.